Line data Source code
1 :
2 : /* pngrutil.c - utilities to read a PNG file
3 : *
4 : * Last changed in libpng 1.6.29 [March 16, 2017]
5 : * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
6 : * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 : * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
8 : *
9 : * This code is released under the libpng license.
10 : * For conditions of distribution and use, see the disclaimer
11 : * and license in png.h
12 : *
13 : * This file contains routines that are only called from within
14 : * libpng itself during the course of reading an image.
15 : */
16 :
17 : #include "pngpriv.h"
18 :
19 : #ifdef PNG_READ_SUPPORTED
20 :
21 : png_uint_32 PNGAPI
22 500 : png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf)
23 : {
24 500 : png_uint_32 uval = png_get_uint_32(buf);
25 :
26 500 : if (uval > PNG_UINT_31_MAX)
27 0 : png_error(png_ptr, "PNG unsigned integer out of range");
28 :
29 500 : return (uval);
30 : }
31 :
32 : #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
33 : /* The following is a variation on the above for use with the fixed
34 : * point values used for gAMA and cHRM. Instead of png_error it
35 : * issues a warning and returns (-1) - an invalid value because both
36 : * gAMA and cHRM use *unsigned* integers for fixed point values.
37 : */
38 : #define PNG_FIXED_ERROR (-1)
39 :
40 : static png_fixed_point /* PRIVATE */
41 0 : png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf)
42 : {
43 0 : png_uint_32 uval = png_get_uint_32(buf);
44 :
45 0 : if (uval <= PNG_UINT_31_MAX)
46 0 : return (png_fixed_point)uval; /* known to be in range */
47 :
48 : /* The caller can turn off the warning by passing NULL. */
49 0 : if (png_ptr != NULL)
50 0 : png_warning(png_ptr, "PNG fixed point integer out of range");
51 :
52 0 : return PNG_FIXED_ERROR;
53 : }
54 : #endif
55 :
56 : #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
57 : /* NOTE: the read macros will obscure these definitions, so that if
58 : * PNG_USE_READ_MACROS is set the library will not use them internally,
59 : * but the APIs will still be available externally.
60 : *
61 : * The parentheses around "PNGAPI function_name" in the following three
62 : * functions are necessary because they allow the macros to co-exist with
63 : * these (unused but exported) functions.
64 : */
65 :
66 : /* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
67 : png_uint_32 (PNGAPI
68 : png_get_uint_32)(png_const_bytep buf)
69 : {
70 : png_uint_32 uval =
71 : ((png_uint_32)(*(buf )) << 24) +
72 : ((png_uint_32)(*(buf + 1)) << 16) +
73 : ((png_uint_32)(*(buf + 2)) << 8) +
74 : ((png_uint_32)(*(buf + 3)) ) ;
75 :
76 : return uval;
77 : }
78 :
79 : /* Grab a signed 32-bit integer from a buffer in big-endian format. The
80 : * data is stored in the PNG file in two's complement format and there
81 : * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore
82 : * the following code does a two's complement to native conversion.
83 : */
84 : png_int_32 (PNGAPI
85 : png_get_int_32)(png_const_bytep buf)
86 : {
87 : png_uint_32 uval = png_get_uint_32(buf);
88 : if ((uval & 0x80000000) == 0) /* non-negative */
89 : return (png_int_32)uval;
90 :
91 : uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */
92 : if ((uval & 0x80000000) == 0) /* no overflow */
93 : return -(png_int_32)uval;
94 : /* The following has to be safe; this function only gets called on PNG data
95 : * and if we get here that data is invalid. 0 is the most safe value and
96 : * if not then an attacker would surely just generate a PNG with 0 instead.
97 : */
98 : return 0;
99 : }
100 :
101 : /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
102 : png_uint_16 (PNGAPI
103 : png_get_uint_16)(png_const_bytep buf)
104 : {
105 : /* ANSI-C requires an int value to accomodate at least 16 bits so this
106 : * works and allows the compiler not to worry about possible narrowing
107 : * on 32-bit systems. (Pre-ANSI systems did not make integers smaller
108 : * than 16 bits either.)
109 : */
110 : unsigned int val =
111 : ((unsigned int)(*buf) << 8) +
112 : ((unsigned int)(*(buf + 1)));
113 :
114 : return (png_uint_16)val;
115 : }
116 :
117 : #endif /* READ_INT_FUNCTIONS */
118 :
119 : /* Read and check the PNG file signature */
120 : void /* PRIVATE */
121 0 : png_read_sig(png_structrp png_ptr, png_inforp info_ptr)
122 : {
123 : png_size_t num_checked, num_to_check;
124 :
125 : /* Exit if the user application does not expect a signature. */
126 0 : if (png_ptr->sig_bytes >= 8)
127 0 : return;
128 :
129 0 : num_checked = png_ptr->sig_bytes;
130 0 : num_to_check = 8 - num_checked;
131 :
132 : #ifdef PNG_IO_STATE_SUPPORTED
133 : png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
134 : #endif
135 :
136 : /* The signature must be serialized in a single I/O call. */
137 0 : png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
138 0 : png_ptr->sig_bytes = 8;
139 :
140 0 : if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check) != 0)
141 : {
142 0 : if (num_checked < 4 &&
143 0 : png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
144 0 : png_error(png_ptr, "Not a PNG file");
145 : else
146 0 : png_error(png_ptr, "PNG file corrupted by ASCII conversion");
147 : }
148 0 : if (num_checked < 3)
149 0 : png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
150 : }
151 :
152 : /* Read the chunk header (length + type name).
153 : * Put the type name into png_ptr->chunk_name, and return the length.
154 : */
155 : png_uint_32 /* PRIVATE */
156 0 : png_read_chunk_header(png_structrp png_ptr)
157 : {
158 : png_byte buf[8];
159 : png_uint_32 length;
160 :
161 : #ifdef PNG_IO_STATE_SUPPORTED
162 : png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR;
163 : #endif
164 :
165 : /* Read the length and the chunk name.
166 : * This must be performed in a single I/O call.
167 : */
168 0 : png_read_data(png_ptr, buf, 8);
169 0 : length = png_get_uint_31(png_ptr, buf);
170 :
171 : /* Put the chunk name into png_ptr->chunk_name. */
172 0 : png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4);
173 :
174 : png_debug2(0, "Reading %lx chunk, length = %lu",
175 : (unsigned long)png_ptr->chunk_name, (unsigned long)length);
176 :
177 : /* Reset the crc and run it over the chunk name. */
178 0 : png_reset_crc(png_ptr);
179 0 : png_calculate_crc(png_ptr, buf + 4, 4);
180 :
181 : /* Check to see if chunk name is valid. */
182 0 : png_check_chunk_name(png_ptr, png_ptr->chunk_name);
183 :
184 : #ifdef PNG_IO_STATE_SUPPORTED
185 : png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA;
186 : #endif
187 :
188 0 : return length;
189 : }
190 :
191 : /* Read data, and (optionally) run it through the CRC. */
192 : void /* PRIVATE */
193 514 : png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length)
194 : {
195 514 : if (png_ptr == NULL)
196 0 : return;
197 :
198 514 : png_read_data(png_ptr, buf, length);
199 514 : png_calculate_crc(png_ptr, buf, length);
200 : }
201 :
202 : /* Optionally skip data and then check the CRC. Depending on whether we
203 : * are reading an ancillary or critical chunk, and how the program has set
204 : * things up, we may calculate the CRC on the data and print a message.
205 : * Returns '1' if there was a CRC error, '0' otherwise.
206 : */
207 : int /* PRIVATE */
208 188 : png_crc_finish(png_structrp png_ptr, png_uint_32 skip)
209 : {
210 : /* The size of the local buffer for inflate is a good guess as to a
211 : * reasonable size to use for buffering reads from the application.
212 : */
213 419 : while (skip > 0)
214 : {
215 : png_uint_32 len;
216 : png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
217 :
218 43 : len = (sizeof tmpbuf);
219 43 : if (len > skip)
220 43 : len = skip;
221 43 : skip -= len;
222 :
223 43 : png_crc_read(png_ptr, tmpbuf, len);
224 : }
225 :
226 188 : if (png_crc_error(png_ptr) != 0)
227 : {
228 0 : if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0 ?
229 0 : (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0 :
230 0 : (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0)
231 : {
232 0 : png_chunk_warning(png_ptr, "CRC error");
233 : }
234 :
235 : else
236 0 : png_chunk_error(png_ptr, "CRC error");
237 :
238 0 : return (1);
239 : }
240 :
241 188 : return (0);
242 : }
243 :
244 : /* Compare the CRC stored in the PNG file with that calculated by libpng from
245 : * the data it has read thus far.
246 : */
247 : int /* PRIVATE */
248 188 : png_crc_error(png_structrp png_ptr)
249 : {
250 : png_byte crc_bytes[4];
251 : png_uint_32 crc;
252 188 : int need_crc = 1;
253 :
254 188 : if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
255 : {
256 129 : if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
257 : (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
258 0 : need_crc = 0;
259 : }
260 :
261 : else /* critical */
262 : {
263 59 : if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
264 0 : need_crc = 0;
265 : }
266 :
267 : #ifdef PNG_IO_STATE_SUPPORTED
268 : png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
269 : #endif
270 :
271 : /* The chunk CRC must be serialized in a single I/O call. */
272 188 : png_read_data(png_ptr, crc_bytes, 4);
273 :
274 188 : if (need_crc != 0)
275 : {
276 188 : crc = png_get_uint_32(crc_bytes);
277 188 : return ((int)(crc != png_ptr->crc));
278 : }
279 :
280 : else
281 0 : return (0);
282 : }
283 :
284 : #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
285 : defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
286 : defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
287 : defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
288 : /* Manage the read buffer; this simply reallocates the buffer if it is not small
289 : * enough (or if it is not allocated). The routine returns a pointer to the
290 : * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
291 : * it will call png_error (via png_malloc) on failure. (warn == 2 means
292 : * 'silent').
293 : */
294 : static png_bytep
295 0 : png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn)
296 : {
297 0 : png_bytep buffer = png_ptr->read_buffer;
298 :
299 0 : if (buffer != NULL && new_size > png_ptr->read_buffer_size)
300 : {
301 0 : png_ptr->read_buffer = NULL;
302 0 : png_ptr->read_buffer = NULL;
303 0 : png_ptr->read_buffer_size = 0;
304 0 : png_free(png_ptr, buffer);
305 0 : buffer = NULL;
306 : }
307 :
308 0 : if (buffer == NULL)
309 : {
310 0 : buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size));
311 :
312 0 : if (buffer != NULL)
313 : {
314 0 : png_ptr->read_buffer = buffer;
315 0 : png_ptr->read_buffer_size = new_size;
316 : }
317 :
318 0 : else if (warn < 2) /* else silent */
319 : {
320 0 : if (warn != 0)
321 0 : png_chunk_warning(png_ptr, "insufficient memory to read chunk");
322 :
323 : else
324 0 : png_chunk_error(png_ptr, "insufficient memory to read chunk");
325 : }
326 : }
327 :
328 0 : return buffer;
329 : }
330 : #endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
331 :
332 : /* png_inflate_claim: claim the zstream for some nefarious purpose that involves
333 : * decompression. Returns Z_OK on success, else a zlib error code. It checks
334 : * the owner but, in final release builds, just issues a warning if some other
335 : * chunk apparently owns the stream. Prior to release it does a png_error.
336 : */
337 : static int
338 31 : png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
339 : {
340 31 : if (png_ptr->zowner != 0)
341 : {
342 : char msg[64];
343 :
344 0 : PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner);
345 : /* So the message that results is "<chunk> using zstream"; this is an
346 : * internal error, but is very useful for debugging. i18n requirements
347 : * are minimal.
348 : */
349 0 : (void)png_safecat(msg, (sizeof msg), 4, " using zstream");
350 : #if PNG_RELEASE_BUILD
351 0 : png_chunk_warning(png_ptr, msg);
352 0 : png_ptr->zowner = 0;
353 : #else
354 : png_chunk_error(png_ptr, msg);
355 : #endif
356 : }
357 :
358 : /* Implementation note: unlike 'png_deflate_claim' this internal function
359 : * does not take the size of the data as an argument. Some efficiency could
360 : * be gained by using this when it is known *if* the zlib stream itself does
361 : * not record the number; however, this is an illusion: the original writer
362 : * of the PNG may have selected a lower window size, and we really must
363 : * follow that because, for systems with with limited capabilities, we
364 : * would otherwise reject the application's attempts to use a smaller window
365 : * size (zlib doesn't have an interface to say "this or lower"!).
366 : *
367 : * inflateReset2 was added to zlib 1.2.4; before this the window could not be
368 : * reset, therefore it is necessary to always allocate the maximum window
369 : * size with earlier zlibs just in case later compressed chunks need it.
370 : */
371 : {
372 : int ret; /* zlib return code */
373 : #if ZLIB_VERNUM >= 0x1240
374 31 : int window_bits = 0;
375 :
376 : # if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
377 31 : if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) ==
378 : PNG_OPTION_ON)
379 : {
380 31 : window_bits = 15;
381 31 : png_ptr->zstream_start = 0; /* fixed window size */
382 : }
383 :
384 : else
385 : {
386 0 : png_ptr->zstream_start = 1;
387 : }
388 : # endif
389 :
390 : #endif /* ZLIB_VERNUM >= 0x1240 */
391 :
392 : /* Set this for safety, just in case the previous owner left pointers to
393 : * memory allocations.
394 : */
395 31 : png_ptr->zstream.next_in = NULL;
396 31 : png_ptr->zstream.avail_in = 0;
397 31 : png_ptr->zstream.next_out = NULL;
398 31 : png_ptr->zstream.avail_out = 0;
399 :
400 31 : if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
401 : {
402 : #if ZLIB_VERNUM >= 0x1240
403 0 : ret = inflateReset2(&png_ptr->zstream, window_bits);
404 : #else
405 : ret = inflateReset(&png_ptr->zstream);
406 : #endif
407 : }
408 :
409 : else
410 : {
411 : #if ZLIB_VERNUM >= 0x1240
412 31 : ret = inflateInit2(&png_ptr->zstream, window_bits);
413 : #else
414 : ret = inflateInit(&png_ptr->zstream);
415 : #endif
416 :
417 31 : if (ret == Z_OK)
418 31 : png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
419 : }
420 :
421 : #if ZLIB_VERNUM >= 0x1290 && \
422 : defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_IGNORE_ADLER32)
423 31 : if (((png_ptr->options >> PNG_IGNORE_ADLER32) & 3) == PNG_OPTION_ON)
424 : /* Turn off validation of the ADLER32 checksum in IDAT chunks */
425 0 : ret = inflateValidate(&png_ptr->zstream, 0);
426 : #endif
427 :
428 31 : if (ret == Z_OK)
429 31 : png_ptr->zowner = owner;
430 :
431 : else
432 0 : png_zstream_error(png_ptr, ret);
433 :
434 31 : return ret;
435 : }
436 :
437 : #ifdef window_bits
438 : # undef window_bits
439 : #endif
440 : }
441 :
442 : #if ZLIB_VERNUM >= 0x1240
443 : /* Handle the start of the inflate stream if we called inflateInit2(strm,0);
444 : * in this case some zlib versions skip validation of the CINFO field and, in
445 : * certain circumstances, libpng may end up displaying an invalid image, in
446 : * contrast to implementations that call zlib in the normal way (e.g. libpng
447 : * 1.5).
448 : */
449 : int /* PRIVATE */
450 1539 : png_zlib_inflate(png_structrp png_ptr, int flush)
451 : {
452 1539 : if (png_ptr->zstream_start && png_ptr->zstream.avail_in > 0)
453 : {
454 0 : if ((*png_ptr->zstream.next_in >> 4) > 7)
455 : {
456 0 : png_ptr->zstream.msg = "invalid window size (libpng)";
457 0 : return Z_DATA_ERROR;
458 : }
459 :
460 0 : png_ptr->zstream_start = 0;
461 : }
462 :
463 1539 : return inflate(&png_ptr->zstream, flush);
464 : }
465 : #endif /* Zlib >= 1.2.4 */
466 :
467 : #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
468 : #if defined(PNG_READ_zTXt_SUPPORTED) || defined (PNG_READ_iTXt_SUPPORTED)
469 : /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
470 : * allow the caller to do multiple calls if required. If the 'finish' flag is
471 : * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
472 : * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
473 : * Z_OK or Z_STREAM_END will be returned on success.
474 : *
475 : * The input and output sizes are updated to the actual amounts of data consumed
476 : * or written, not the amount available (as in a z_stream). The data pointers
477 : * are not changed, so the next input is (data+input_size) and the next
478 : * available output is (output+output_size).
479 : */
480 : static int
481 : png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
482 : /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr,
483 : /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr)
484 : {
485 : if (png_ptr->zowner == owner) /* Else not claimed */
486 : {
487 : int ret;
488 : png_alloc_size_t avail_out = *output_size_ptr;
489 : png_uint_32 avail_in = *input_size_ptr;
490 :
491 : /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
492 : * can't even necessarily handle 65536 bytes) because the type uInt is
493 : * "16 bits or more". Consequently it is necessary to chunk the input to
494 : * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
495 : * maximum value that can be stored in a uInt.) It is possible to set
496 : * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
497 : * a performance advantage, because it reduces the amount of data accessed
498 : * at each step and that may give the OS more time to page it in.
499 : */
500 : png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
501 : /* avail_in and avail_out are set below from 'size' */
502 : png_ptr->zstream.avail_in = 0;
503 : png_ptr->zstream.avail_out = 0;
504 :
505 : /* Read directly into the output if it is available (this is set to
506 : * a local buffer below if output is NULL).
507 : */
508 : if (output != NULL)
509 : png_ptr->zstream.next_out = output;
510 :
511 : do
512 : {
513 : uInt avail;
514 : Byte local_buffer[PNG_INFLATE_BUF_SIZE];
515 :
516 : /* zlib INPUT BUFFER */
517 : /* The setting of 'avail_in' used to be outside the loop; by setting it
518 : * inside it is possible to chunk the input to zlib and simply rely on
519 : * zlib to advance the 'next_in' pointer. This allows arbitrary
520 : * amounts of data to be passed through zlib at the unavoidable cost of
521 : * requiring a window save (memcpy of up to 32768 output bytes)
522 : * every ZLIB_IO_MAX input bytes.
523 : */
524 : avail_in += png_ptr->zstream.avail_in; /* not consumed last time */
525 :
526 : avail = ZLIB_IO_MAX;
527 :
528 : if (avail_in < avail)
529 : avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */
530 :
531 : avail_in -= avail;
532 : png_ptr->zstream.avail_in = avail;
533 :
534 : /* zlib OUTPUT BUFFER */
535 : avail_out += png_ptr->zstream.avail_out; /* not written last time */
536 :
537 : avail = ZLIB_IO_MAX; /* maximum zlib can process */
538 :
539 : if (output == NULL)
540 : {
541 : /* Reset the output buffer each time round if output is NULL and
542 : * make available the full buffer, up to 'remaining_space'
543 : */
544 : png_ptr->zstream.next_out = local_buffer;
545 : if ((sizeof local_buffer) < avail)
546 : avail = (sizeof local_buffer);
547 : }
548 :
549 : if (avail_out < avail)
550 : avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */
551 :
552 : png_ptr->zstream.avail_out = avail;
553 : avail_out -= avail;
554 :
555 : /* zlib inflate call */
556 : /* In fact 'avail_out' may be 0 at this point, that happens at the end
557 : * of the read when the final LZ end code was not passed at the end of
558 : * the previous chunk of input data. Tell zlib if we have reached the
559 : * end of the output buffer.
560 : */
561 : ret = PNG_INFLATE(png_ptr, avail_out > 0 ? Z_NO_FLUSH :
562 : (finish ? Z_FINISH : Z_SYNC_FLUSH));
563 : } while (ret == Z_OK);
564 :
565 : /* For safety kill the local buffer pointer now */
566 : if (output == NULL)
567 : png_ptr->zstream.next_out = NULL;
568 :
569 : /* Claw back the 'size' and 'remaining_space' byte counts. */
570 : avail_in += png_ptr->zstream.avail_in;
571 : avail_out += png_ptr->zstream.avail_out;
572 :
573 : /* Update the input and output sizes; the updated values are the amount
574 : * consumed or written, effectively the inverse of what zlib uses.
575 : */
576 : if (avail_out > 0)
577 : *output_size_ptr -= avail_out;
578 :
579 : if (avail_in > 0)
580 : *input_size_ptr -= avail_in;
581 :
582 : /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
583 : png_zstream_error(png_ptr, ret);
584 : return ret;
585 : }
586 :
587 : else
588 : {
589 : /* This is a bad internal error. The recovery assigns to the zstream msg
590 : * pointer, which is not owned by the caller, but this is safe; it's only
591 : * used on errors!
592 : */
593 : png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
594 : return Z_STREAM_ERROR;
595 : }
596 : }
597 :
598 : /*
599 : * Decompress trailing data in a chunk. The assumption is that read_buffer
600 : * points at an allocated area holding the contents of a chunk with a
601 : * trailing compressed part. What we get back is an allocated area
602 : * holding the original prefix part and an uncompressed version of the
603 : * trailing part (the malloc area passed in is freed).
604 : */
605 : static int
606 : png_decompress_chunk(png_structrp png_ptr,
607 : png_uint_32 chunklength, png_uint_32 prefix_size,
608 : png_alloc_size_t *newlength /* must be initialized to the maximum! */,
609 : int terminate /*add a '\0' to the end of the uncompressed data*/)
610 : {
611 : /* TODO: implement different limits for different types of chunk.
612 : *
613 : * The caller supplies *newlength set to the maximum length of the
614 : * uncompressed data, but this routine allocates space for the prefix and
615 : * maybe a '\0' terminator too. We have to assume that 'prefix_size' is
616 : * limited only by the maximum chunk size.
617 : */
618 : png_alloc_size_t limit = PNG_SIZE_MAX;
619 :
620 : # ifdef PNG_SET_USER_LIMITS_SUPPORTED
621 : if (png_ptr->user_chunk_malloc_max > 0 &&
622 : png_ptr->user_chunk_malloc_max < limit)
623 : limit = png_ptr->user_chunk_malloc_max;
624 : # elif PNG_USER_CHUNK_MALLOC_MAX > 0
625 : if (PNG_USER_CHUNK_MALLOC_MAX < limit)
626 : limit = PNG_USER_CHUNK_MALLOC_MAX;
627 : # endif
628 :
629 : if (limit >= prefix_size + (terminate != 0))
630 : {
631 : int ret;
632 :
633 : limit -= prefix_size + (terminate != 0);
634 :
635 : if (limit < *newlength)
636 : *newlength = limit;
637 :
638 : /* Now try to claim the stream. */
639 : ret = png_inflate_claim(png_ptr, png_ptr->chunk_name);
640 :
641 : if (ret == Z_OK)
642 : {
643 : png_uint_32 lzsize = chunklength - prefix_size;
644 :
645 : ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
646 : /* input: */ png_ptr->read_buffer + prefix_size, &lzsize,
647 : /* output: */ NULL, newlength);
648 :
649 : if (ret == Z_STREAM_END)
650 : {
651 : /* Use 'inflateReset' here, not 'inflateReset2' because this
652 : * preserves the previously decided window size (otherwise it would
653 : * be necessary to store the previous window size.) In practice
654 : * this doesn't matter anyway, because png_inflate will call inflate
655 : * with Z_FINISH in almost all cases, so the window will not be
656 : * maintained.
657 : */
658 : if (inflateReset(&png_ptr->zstream) == Z_OK)
659 : {
660 : /* Because of the limit checks above we know that the new,
661 : * expanded, size will fit in a size_t (let alone an
662 : * png_alloc_size_t). Use png_malloc_base here to avoid an
663 : * extra OOM message.
664 : */
665 : png_alloc_size_t new_size = *newlength;
666 : png_alloc_size_t buffer_size = prefix_size + new_size +
667 : (terminate != 0);
668 : png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr,
669 : buffer_size));
670 :
671 : if (text != NULL)
672 : {
673 : ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
674 : png_ptr->read_buffer + prefix_size, &lzsize,
675 : text + prefix_size, newlength);
676 :
677 : if (ret == Z_STREAM_END)
678 : {
679 : if (new_size == *newlength)
680 : {
681 : if (terminate != 0)
682 : text[prefix_size + *newlength] = 0;
683 :
684 : if (prefix_size > 0)
685 : memcpy(text, png_ptr->read_buffer, prefix_size);
686 :
687 : {
688 : png_bytep old_ptr = png_ptr->read_buffer;
689 :
690 : png_ptr->read_buffer = text;
691 : png_ptr->read_buffer_size = buffer_size;
692 : text = old_ptr; /* freed below */
693 : }
694 : }
695 :
696 : else
697 : {
698 : /* The size changed on the second read, there can be no
699 : * guarantee that anything is correct at this point.
700 : * The 'msg' pointer has been set to "unexpected end of
701 : * LZ stream", which is fine, but return an error code
702 : * that the caller won't accept.
703 : */
704 : ret = PNG_UNEXPECTED_ZLIB_RETURN;
705 : }
706 : }
707 :
708 : else if (ret == Z_OK)
709 : ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */
710 :
711 : /* Free the text pointer (this is the old read_buffer on
712 : * success)
713 : */
714 : png_free(png_ptr, text);
715 :
716 : /* This really is very benign, but it's still an error because
717 : * the extra space may otherwise be used as a Trojan Horse.
718 : */
719 : if (ret == Z_STREAM_END &&
720 : chunklength - prefix_size != lzsize)
721 : png_chunk_benign_error(png_ptr, "extra compressed data");
722 : }
723 :
724 : else
725 : {
726 : /* Out of memory allocating the buffer */
727 : ret = Z_MEM_ERROR;
728 : png_zstream_error(png_ptr, Z_MEM_ERROR);
729 : }
730 : }
731 :
732 : else
733 : {
734 : /* inflateReset failed, store the error message */
735 : png_zstream_error(png_ptr, ret);
736 :
737 : if (ret == Z_STREAM_END)
738 : ret = PNG_UNEXPECTED_ZLIB_RETURN;
739 : }
740 : }
741 :
742 : else if (ret == Z_OK)
743 : ret = PNG_UNEXPECTED_ZLIB_RETURN;
744 :
745 : /* Release the claimed stream */
746 : png_ptr->zowner = 0;
747 : }
748 :
749 : else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */
750 : ret = PNG_UNEXPECTED_ZLIB_RETURN;
751 :
752 : return ret;
753 : }
754 :
755 : else
756 : {
757 : /* Application/configuration limits exceeded */
758 : png_zstream_error(png_ptr, Z_MEM_ERROR);
759 : return Z_MEM_ERROR;
760 : }
761 : }
762 : #endif /* READ_zTXt || READ_iTXt */
763 : #endif /* READ_COMPRESSED_TEXT */
764 :
765 : #ifdef PNG_READ_iCCP_SUPPORTED
766 : /* Perform a partial read and decompress, producing 'avail_out' bytes and
767 : * reading from the current chunk as required.
768 : */
769 : static int
770 0 : png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
771 : png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size,
772 : int finish)
773 : {
774 0 : if (png_ptr->zowner == png_ptr->chunk_name)
775 : {
776 : int ret;
777 :
778 : /* next_in and avail_in must have been initialized by the caller. */
779 0 : png_ptr->zstream.next_out = next_out;
780 0 : png_ptr->zstream.avail_out = 0; /* set in the loop */
781 :
782 : do
783 : {
784 0 : if (png_ptr->zstream.avail_in == 0)
785 : {
786 0 : if (read_size > *chunk_bytes)
787 0 : read_size = (uInt)*chunk_bytes;
788 0 : *chunk_bytes -= read_size;
789 :
790 0 : if (read_size > 0)
791 0 : png_crc_read(png_ptr, read_buffer, read_size);
792 :
793 0 : png_ptr->zstream.next_in = read_buffer;
794 0 : png_ptr->zstream.avail_in = read_size;
795 : }
796 :
797 0 : if (png_ptr->zstream.avail_out == 0)
798 : {
799 0 : uInt avail = ZLIB_IO_MAX;
800 0 : if (avail > *out_size)
801 0 : avail = (uInt)*out_size;
802 0 : *out_size -= avail;
803 :
804 0 : png_ptr->zstream.avail_out = avail;
805 : }
806 :
807 : /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
808 : * the available output is produced; this allows reading of truncated
809 : * streams.
810 : */
811 0 : ret = PNG_INFLATE(png_ptr, *chunk_bytes > 0 ?
812 : Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH));
813 : }
814 0 : while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0));
815 :
816 0 : *out_size += png_ptr->zstream.avail_out;
817 0 : png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */
818 :
819 : /* Ensure the error message pointer is always set: */
820 0 : png_zstream_error(png_ptr, ret);
821 0 : return ret;
822 : }
823 :
824 : else
825 : {
826 0 : png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
827 0 : return Z_STREAM_ERROR;
828 : }
829 : }
830 : #endif /* READ_iCCP */
831 :
832 : /* Read and check the IDHR chunk */
833 :
834 : void /* PRIVATE */
835 31 : png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
836 : {
837 : png_byte buf[13];
838 : png_uint_32 width, height;
839 : int bit_depth, color_type, compression_type, filter_type;
840 : int interlace_type;
841 :
842 : png_debug(1, "in png_handle_IHDR");
843 :
844 31 : if ((png_ptr->mode & PNG_HAVE_IHDR) != 0)
845 0 : png_chunk_error(png_ptr, "out of place");
846 :
847 : /* Check the length */
848 31 : if (length != 13)
849 0 : png_chunk_error(png_ptr, "invalid");
850 :
851 31 : png_ptr->mode |= PNG_HAVE_IHDR;
852 :
853 31 : png_crc_read(png_ptr, buf, 13);
854 31 : png_crc_finish(png_ptr, 0);
855 :
856 31 : width = png_get_uint_31(png_ptr, buf);
857 31 : height = png_get_uint_31(png_ptr, buf + 4);
858 31 : bit_depth = buf[8];
859 31 : color_type = buf[9];
860 31 : compression_type = buf[10];
861 31 : filter_type = buf[11];
862 31 : interlace_type = buf[12];
863 :
864 : #ifdef PNG_READ_APNG_SUPPORTED
865 31 : png_ptr->first_frame_width = width;
866 31 : png_ptr->first_frame_height = height;
867 : #endif
868 :
869 : /* Set internal variables */
870 31 : png_ptr->width = width;
871 31 : png_ptr->height = height;
872 31 : png_ptr->bit_depth = (png_byte)bit_depth;
873 31 : png_ptr->interlaced = (png_byte)interlace_type;
874 31 : png_ptr->color_type = (png_byte)color_type;
875 : #ifdef PNG_MNG_FEATURES_SUPPORTED
876 : png_ptr->filter_type = (png_byte)filter_type;
877 : #endif
878 31 : png_ptr->compression_type = (png_byte)compression_type;
879 :
880 : /* Find number of channels */
881 31 : switch (png_ptr->color_type)
882 : {
883 : default: /* invalid, png_set_IHDR calls png_error */
884 : case PNG_COLOR_TYPE_GRAY:
885 : case PNG_COLOR_TYPE_PALETTE:
886 2 : png_ptr->channels = 1;
887 2 : break;
888 :
889 : case PNG_COLOR_TYPE_RGB:
890 0 : png_ptr->channels = 3;
891 0 : break;
892 :
893 : case PNG_COLOR_TYPE_GRAY_ALPHA:
894 4 : png_ptr->channels = 2;
895 4 : break;
896 :
897 : case PNG_COLOR_TYPE_RGB_ALPHA:
898 25 : png_ptr->channels = 4;
899 25 : break;
900 : }
901 :
902 : /* Set up other useful info */
903 31 : png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels);
904 31 : png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
905 : png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
906 : png_debug1(3, "channels = %d", png_ptr->channels);
907 : png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes);
908 31 : png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
909 : color_type, interlace_type, compression_type, filter_type);
910 31 : }
911 :
912 : /* Read and check the palette */
913 : void /* PRIVATE */
914 2 : png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
915 : {
916 : png_color palette[PNG_MAX_PALETTE_LENGTH];
917 : int max_palette_length, num, i;
918 : #ifdef PNG_POINTER_INDEXING_SUPPORTED
919 : png_colorp pal_ptr;
920 : #endif
921 :
922 : png_debug(1, "in png_handle_PLTE");
923 :
924 2 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
925 0 : png_chunk_error(png_ptr, "missing IHDR");
926 :
927 : /* Moved to before the 'after IDAT' check below because otherwise duplicate
928 : * PLTE chunks are potentially ignored (the spec says there shall not be more
929 : * than one PLTE, the error is not treated as benign, so this check trumps
930 : * the requirement that PLTE appears before IDAT.)
931 : */
932 2 : else if ((png_ptr->mode & PNG_HAVE_PLTE) != 0)
933 0 : png_chunk_error(png_ptr, "duplicate");
934 :
935 2 : else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
936 : {
937 : /* This is benign because the non-benign error happened before, when an
938 : * IDAT was encountered in a color-mapped image with no PLTE.
939 : */
940 0 : png_crc_finish(png_ptr, length);
941 0 : png_chunk_benign_error(png_ptr, "out of place");
942 0 : return;
943 : }
944 :
945 2 : png_ptr->mode |= PNG_HAVE_PLTE;
946 :
947 2 : if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
948 : {
949 0 : png_crc_finish(png_ptr, length);
950 0 : png_chunk_benign_error(png_ptr, "ignored in grayscale PNG");
951 0 : return;
952 : }
953 :
954 : #ifndef PNG_READ_OPT_PLTE_SUPPORTED
955 2 : if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
956 : {
957 0 : png_crc_finish(png_ptr, length);
958 0 : return;
959 : }
960 : #endif
961 :
962 2 : if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
963 : {
964 0 : png_crc_finish(png_ptr, length);
965 :
966 0 : if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
967 0 : png_chunk_benign_error(png_ptr, "invalid");
968 :
969 : else
970 0 : png_chunk_error(png_ptr, "invalid");
971 :
972 0 : return;
973 : }
974 :
975 : /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
976 2 : num = (int)length / 3;
977 :
978 : /* If the palette has 256 or fewer entries but is too large for the bit
979 : * depth, we don't issue an error, to preserve the behavior of previous
980 : * libpng versions. We silently truncate the unused extra palette entries
981 : * here.
982 : */
983 2 : if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
984 2 : max_palette_length = (1 << png_ptr->bit_depth);
985 : else
986 0 : max_palette_length = PNG_MAX_PALETTE_LENGTH;
987 :
988 2 : if (num > max_palette_length)
989 0 : num = max_palette_length;
990 :
991 : #ifdef PNG_POINTER_INDEXING_SUPPORTED
992 112 : for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
993 : {
994 : png_byte buf[3];
995 :
996 110 : png_crc_read(png_ptr, buf, 3);
997 110 : pal_ptr->red = buf[0];
998 110 : pal_ptr->green = buf[1];
999 110 : pal_ptr->blue = buf[2];
1000 : }
1001 : #else
1002 : for (i = 0; i < num; i++)
1003 : {
1004 : png_byte buf[3];
1005 :
1006 : png_crc_read(png_ptr, buf, 3);
1007 : /* Don't depend upon png_color being any order */
1008 : palette[i].red = buf[0];
1009 : palette[i].green = buf[1];
1010 : palette[i].blue = buf[2];
1011 : }
1012 : #endif
1013 :
1014 : /* If we actually need the PLTE chunk (ie for a paletted image), we do
1015 : * whatever the normal CRC configuration tells us. However, if we
1016 : * have an RGB image, the PLTE can be considered ancillary, so
1017 : * we will act as though it is.
1018 : */
1019 : #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1020 2 : if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1021 : #endif
1022 : {
1023 2 : png_crc_finish(png_ptr, (png_uint_32) (length - (unsigned int)num * 3));
1024 : }
1025 :
1026 : #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1027 0 : else if (png_crc_error(png_ptr) != 0) /* Only if we have a CRC error */
1028 : {
1029 : /* If we don't want to use the data from an ancillary chunk,
1030 : * we have two options: an error abort, or a warning and we
1031 : * ignore the data in this chunk (which should be OK, since
1032 : * it's considered ancillary for a RGB or RGBA image).
1033 : *
1034 : * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
1035 : * chunk type to determine whether to check the ancillary or the critical
1036 : * flags.
1037 : */
1038 0 : if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE) == 0)
1039 : {
1040 0 : if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) != 0)
1041 0 : return;
1042 :
1043 : else
1044 0 : png_chunk_error(png_ptr, "CRC error");
1045 : }
1046 :
1047 : /* Otherwise, we (optionally) emit a warning and use the chunk. */
1048 0 : else if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0)
1049 0 : png_chunk_warning(png_ptr, "CRC error");
1050 : }
1051 : #endif
1052 :
1053 : /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
1054 : * own copy of the palette. This has the side effect that when png_start_row
1055 : * is called (this happens after any call to png_read_update_info) the
1056 : * info_ptr palette gets changed. This is extremely unexpected and
1057 : * confusing.
1058 : *
1059 : * Fix this by not sharing the palette in this way.
1060 : */
1061 2 : png_set_PLTE(png_ptr, info_ptr, palette, num);
1062 :
1063 : /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
1064 : * IDAT. Prior to 1.6.0 this was not checked; instead the code merely
1065 : * checked the apparent validity of a tRNS chunk inserted before PLTE on a
1066 : * palette PNG. 1.6.0 attempts to rigorously follow the standard and
1067 : * therefore does a benign error if the erroneous condition is detected *and*
1068 : * cancels the tRNS if the benign error returns. The alternative is to
1069 : * amend the standard since it would be rather hypocritical of the standards
1070 : * maintainers to ignore it.
1071 : */
1072 : #ifdef PNG_READ_tRNS_SUPPORTED
1073 2 : if (png_ptr->num_trans > 0 ||
1074 2 : (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0))
1075 : {
1076 : /* Cancel this because otherwise it would be used if the transforms
1077 : * require it. Don't cancel the 'valid' flag because this would prevent
1078 : * detection of duplicate chunks.
1079 : */
1080 0 : png_ptr->num_trans = 0;
1081 :
1082 0 : if (info_ptr != NULL)
1083 0 : info_ptr->num_trans = 0;
1084 :
1085 0 : png_chunk_benign_error(png_ptr, "tRNS must be after");
1086 : }
1087 : #endif
1088 :
1089 : #ifdef PNG_READ_hIST_SUPPORTED
1090 : if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
1091 : png_chunk_benign_error(png_ptr, "hIST must be after");
1092 : #endif
1093 :
1094 : #ifdef PNG_READ_bKGD_SUPPORTED
1095 : if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1096 : png_chunk_benign_error(png_ptr, "bKGD must be after");
1097 : #endif
1098 : }
1099 :
1100 : void /* PRIVATE */
1101 13 : png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1102 : {
1103 : png_debug(1, "in png_handle_IEND");
1104 :
1105 26 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0 ||
1106 13 : (png_ptr->mode & PNG_HAVE_IDAT) == 0)
1107 0 : png_chunk_error(png_ptr, "out of place");
1108 :
1109 13 : png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
1110 :
1111 13 : png_crc_finish(png_ptr, length);
1112 :
1113 13 : if (length != 0)
1114 0 : png_chunk_benign_error(png_ptr, "invalid");
1115 :
1116 : PNG_UNUSED(info_ptr)
1117 13 : }
1118 :
1119 : #ifdef PNG_READ_gAMA_SUPPORTED
1120 : void /* PRIVATE */
1121 0 : png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1122 : {
1123 : png_fixed_point igamma;
1124 : png_byte buf[4];
1125 :
1126 : png_debug(1, "in png_handle_gAMA");
1127 :
1128 0 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1129 0 : png_chunk_error(png_ptr, "missing IHDR");
1130 :
1131 0 : else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1132 : {
1133 0 : png_crc_finish(png_ptr, length);
1134 0 : png_chunk_benign_error(png_ptr, "out of place");
1135 0 : return;
1136 : }
1137 :
1138 0 : if (length != 4)
1139 : {
1140 0 : png_crc_finish(png_ptr, length);
1141 0 : png_chunk_benign_error(png_ptr, "invalid");
1142 0 : return;
1143 : }
1144 :
1145 0 : png_crc_read(png_ptr, buf, 4);
1146 :
1147 0 : if (png_crc_finish(png_ptr, 0) != 0)
1148 0 : return;
1149 :
1150 0 : igamma = png_get_fixed_point(NULL, buf);
1151 :
1152 0 : png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma);
1153 0 : png_colorspace_sync(png_ptr, info_ptr);
1154 : }
1155 : #endif
1156 :
1157 : #ifdef PNG_READ_sBIT_SUPPORTED
1158 : void /* PRIVATE */
1159 : png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1160 : {
1161 : unsigned int truelen, i;
1162 : png_byte sample_depth;
1163 : png_byte buf[4];
1164 :
1165 : png_debug(1, "in png_handle_sBIT");
1166 :
1167 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1168 : png_chunk_error(png_ptr, "missing IHDR");
1169 :
1170 : else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1171 : {
1172 : png_crc_finish(png_ptr, length);
1173 : png_chunk_benign_error(png_ptr, "out of place");
1174 : return;
1175 : }
1176 :
1177 : if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) != 0)
1178 : {
1179 : png_crc_finish(png_ptr, length);
1180 : png_chunk_benign_error(png_ptr, "duplicate");
1181 : return;
1182 : }
1183 :
1184 : if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1185 : {
1186 : truelen = 3;
1187 : sample_depth = 8;
1188 : }
1189 :
1190 : else
1191 : {
1192 : truelen = png_ptr->channels;
1193 : sample_depth = png_ptr->bit_depth;
1194 : }
1195 :
1196 : if (length != truelen || length > 4)
1197 : {
1198 : png_chunk_benign_error(png_ptr, "invalid");
1199 : png_crc_finish(png_ptr, length);
1200 : return;
1201 : }
1202 :
1203 : buf[0] = buf[1] = buf[2] = buf[3] = sample_depth;
1204 : png_crc_read(png_ptr, buf, truelen);
1205 :
1206 : if (png_crc_finish(png_ptr, 0) != 0)
1207 : return;
1208 :
1209 : for (i=0; i<truelen; ++i)
1210 : {
1211 : if (buf[i] == 0 || buf[i] > sample_depth)
1212 : {
1213 : png_chunk_benign_error(png_ptr, "invalid");
1214 : return;
1215 : }
1216 : }
1217 :
1218 : if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
1219 : {
1220 : png_ptr->sig_bit.red = buf[0];
1221 : png_ptr->sig_bit.green = buf[1];
1222 : png_ptr->sig_bit.blue = buf[2];
1223 : png_ptr->sig_bit.alpha = buf[3];
1224 : }
1225 :
1226 : else
1227 : {
1228 : png_ptr->sig_bit.gray = buf[0];
1229 : png_ptr->sig_bit.red = buf[0];
1230 : png_ptr->sig_bit.green = buf[0];
1231 : png_ptr->sig_bit.blue = buf[0];
1232 : png_ptr->sig_bit.alpha = buf[1];
1233 : }
1234 :
1235 : png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
1236 : }
1237 : #endif
1238 :
1239 : #ifdef PNG_READ_cHRM_SUPPORTED
1240 : void /* PRIVATE */
1241 0 : png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1242 : {
1243 : png_byte buf[32];
1244 : png_xy xy;
1245 :
1246 : png_debug(1, "in png_handle_cHRM");
1247 :
1248 0 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1249 0 : png_chunk_error(png_ptr, "missing IHDR");
1250 :
1251 0 : else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1252 : {
1253 0 : png_crc_finish(png_ptr, length);
1254 0 : png_chunk_benign_error(png_ptr, "out of place");
1255 0 : return;
1256 : }
1257 :
1258 0 : if (length != 32)
1259 : {
1260 0 : png_crc_finish(png_ptr, length);
1261 0 : png_chunk_benign_error(png_ptr, "invalid");
1262 0 : return;
1263 : }
1264 :
1265 0 : png_crc_read(png_ptr, buf, 32);
1266 :
1267 0 : if (png_crc_finish(png_ptr, 0) != 0)
1268 0 : return;
1269 :
1270 0 : xy.whitex = png_get_fixed_point(NULL, buf);
1271 0 : xy.whitey = png_get_fixed_point(NULL, buf + 4);
1272 0 : xy.redx = png_get_fixed_point(NULL, buf + 8);
1273 0 : xy.redy = png_get_fixed_point(NULL, buf + 12);
1274 0 : xy.greenx = png_get_fixed_point(NULL, buf + 16);
1275 0 : xy.greeny = png_get_fixed_point(NULL, buf + 20);
1276 0 : xy.bluex = png_get_fixed_point(NULL, buf + 24);
1277 0 : xy.bluey = png_get_fixed_point(NULL, buf + 28);
1278 :
1279 0 : if (xy.whitex == PNG_FIXED_ERROR ||
1280 0 : xy.whitey == PNG_FIXED_ERROR ||
1281 0 : xy.redx == PNG_FIXED_ERROR ||
1282 0 : xy.redy == PNG_FIXED_ERROR ||
1283 0 : xy.greenx == PNG_FIXED_ERROR ||
1284 0 : xy.greeny == PNG_FIXED_ERROR ||
1285 0 : xy.bluex == PNG_FIXED_ERROR ||
1286 0 : xy.bluey == PNG_FIXED_ERROR)
1287 : {
1288 0 : png_chunk_benign_error(png_ptr, "invalid values");
1289 0 : return;
1290 : }
1291 :
1292 : /* If a colorspace error has already been output skip this chunk */
1293 0 : if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1294 0 : return;
1295 :
1296 0 : if ((png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0)
1297 : {
1298 0 : png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1299 0 : png_colorspace_sync(png_ptr, info_ptr);
1300 0 : png_chunk_benign_error(png_ptr, "duplicate");
1301 0 : return;
1302 : }
1303 :
1304 0 : png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
1305 0 : (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy,
1306 : 1/*prefer cHRM values*/);
1307 0 : png_colorspace_sync(png_ptr, info_ptr);
1308 : }
1309 : #endif
1310 :
1311 : #ifdef PNG_READ_sRGB_SUPPORTED
1312 : void /* PRIVATE */
1313 8 : png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1314 : {
1315 : png_byte intent;
1316 :
1317 : png_debug(1, "in png_handle_sRGB");
1318 :
1319 8 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1320 0 : png_chunk_error(png_ptr, "missing IHDR");
1321 :
1322 8 : else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1323 : {
1324 0 : png_crc_finish(png_ptr, length);
1325 0 : png_chunk_benign_error(png_ptr, "out of place");
1326 0 : return;
1327 : }
1328 :
1329 8 : if (length != 1)
1330 : {
1331 0 : png_crc_finish(png_ptr, length);
1332 0 : png_chunk_benign_error(png_ptr, "invalid");
1333 0 : return;
1334 : }
1335 :
1336 8 : png_crc_read(png_ptr, &intent, 1);
1337 :
1338 8 : if (png_crc_finish(png_ptr, 0) != 0)
1339 0 : return;
1340 :
1341 : /* If a colorspace error has already been output skip this chunk */
1342 8 : if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1343 0 : return;
1344 :
1345 : /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1346 : * this.
1347 : */
1348 8 : if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) != 0)
1349 : {
1350 0 : png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1351 0 : png_colorspace_sync(png_ptr, info_ptr);
1352 0 : png_chunk_benign_error(png_ptr, "too many profiles");
1353 0 : return;
1354 : }
1355 :
1356 8 : (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent);
1357 8 : png_colorspace_sync(png_ptr, info_ptr);
1358 : }
1359 : #endif /* READ_sRGB */
1360 :
1361 : #ifdef PNG_READ_iCCP_SUPPORTED
1362 : void /* PRIVATE */
1363 0 : png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1364 : /* Note: this does not properly handle profiles that are > 64K under DOS */
1365 : {
1366 0 : png_const_charp errmsg = NULL; /* error message output, or no error */
1367 0 : int finished = 0; /* crc checked */
1368 :
1369 : png_debug(1, "in png_handle_iCCP");
1370 :
1371 0 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1372 0 : png_chunk_error(png_ptr, "missing IHDR");
1373 :
1374 0 : else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1375 : {
1376 0 : png_crc_finish(png_ptr, length);
1377 0 : png_chunk_benign_error(png_ptr, "out of place");
1378 0 : return;
1379 : }
1380 :
1381 : /* Consistent with all the above colorspace handling an obviously *invalid*
1382 : * chunk is just ignored, so does not invalidate the color space. An
1383 : * alternative is to set the 'invalid' flags at the start of this routine
1384 : * and only clear them in they were not set before and all the tests pass.
1385 : * The minimum 'deflate' stream is assumed to be just the 2 byte header and
1386 : * 4 byte checksum. The keyword must be at least one character and there is
1387 : * a terminator (0) byte and the compression method.
1388 : */
1389 0 : if (length < 9)
1390 : {
1391 0 : png_crc_finish(png_ptr, length);
1392 0 : png_chunk_benign_error(png_ptr, "too short");
1393 0 : return;
1394 : }
1395 :
1396 : /* If a colorspace error has already been output skip this chunk */
1397 0 : if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1398 : {
1399 0 : png_crc_finish(png_ptr, length);
1400 0 : return;
1401 : }
1402 :
1403 : /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1404 : * this.
1405 : */
1406 0 : if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0)
1407 : {
1408 : uInt read_length, keyword_length;
1409 : char keyword[81];
1410 :
1411 : /* Find the keyword; the keyword plus separator and compression method
1412 : * bytes can be at most 81 characters long.
1413 : */
1414 0 : read_length = 81; /* maximum */
1415 0 : if (read_length > length)
1416 0 : read_length = (uInt)length;
1417 :
1418 0 : png_crc_read(png_ptr, (png_bytep)keyword, read_length);
1419 0 : length -= read_length;
1420 :
1421 0 : keyword_length = 0;
1422 0 : while (keyword_length < 80 && keyword_length < read_length &&
1423 0 : keyword[keyword_length] != 0)
1424 0 : ++keyword_length;
1425 :
1426 : /* TODO: make the keyword checking common */
1427 0 : if (keyword_length >= 1 && keyword_length <= 79)
1428 : {
1429 : /* We only understand '0' compression - deflate - so if we get a
1430 : * different value we can't safely decode the chunk.
1431 : */
1432 0 : if (keyword_length+1 < read_length &&
1433 0 : keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE)
1434 : {
1435 0 : read_length -= keyword_length+2;
1436 :
1437 0 : if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK)
1438 : {
1439 : Byte profile_header[132];
1440 : Byte local_buffer[PNG_INFLATE_BUF_SIZE];
1441 0 : png_alloc_size_t size = (sizeof profile_header);
1442 :
1443 0 : png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2);
1444 0 : png_ptr->zstream.avail_in = read_length;
1445 0 : (void)png_inflate_read(png_ptr, local_buffer,
1446 : (sizeof local_buffer), &length, profile_header, &size,
1447 : 0/*finish: don't, because the output is too small*/);
1448 :
1449 0 : if (size == 0)
1450 : {
1451 : /* We have the ICC profile header; do the basic header checks.
1452 : */
1453 0 : const png_uint_32 profile_length =
1454 0 : png_get_uint_32(profile_header);
1455 :
1456 0 : if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
1457 : keyword, profile_length) != 0)
1458 : {
1459 : /* The length is apparently ok, so we can check the 132
1460 : * byte header.
1461 : */
1462 0 : if (png_icc_check_header(png_ptr, &png_ptr->colorspace,
1463 : keyword, profile_length, profile_header,
1464 0 : png_ptr->color_type) != 0)
1465 : {
1466 : /* Now read the tag table; a variable size buffer is
1467 : * needed at this point, allocate one for the whole
1468 : * profile. The header check has already validated
1469 : * that none of these stuff will overflow.
1470 : */
1471 0 : const png_uint_32 tag_count = png_get_uint_32(
1472 : profile_header+128);
1473 0 : png_bytep profile = png_read_buffer(png_ptr,
1474 : profile_length, 2/*silent*/);
1475 :
1476 0 : if (profile != NULL)
1477 : {
1478 0 : memcpy(profile, profile_header,
1479 : (sizeof profile_header));
1480 :
1481 0 : size = 12 * tag_count;
1482 :
1483 0 : (void)png_inflate_read(png_ptr, local_buffer,
1484 : (sizeof local_buffer), &length,
1485 : profile + (sizeof profile_header), &size, 0);
1486 :
1487 : /* Still expect a buffer error because we expect
1488 : * there to be some tag data!
1489 : */
1490 0 : if (size == 0)
1491 : {
1492 0 : if (png_icc_check_tag_table(png_ptr,
1493 0 : &png_ptr->colorspace, keyword, profile_length,
1494 : profile) != 0)
1495 : {
1496 : /* The profile has been validated for basic
1497 : * security issues, so read the whole thing in.
1498 : */
1499 0 : size = profile_length - (sizeof profile_header)
1500 0 : - 12 * tag_count;
1501 :
1502 0 : (void)png_inflate_read(png_ptr, local_buffer,
1503 : (sizeof local_buffer), &length,
1504 0 : profile + (sizeof profile_header) +
1505 0 : 12 * tag_count, &size, 1/*finish*/);
1506 :
1507 0 : if (length > 0 && !(png_ptr->flags &
1508 : PNG_FLAG_BENIGN_ERRORS_WARN))
1509 0 : errmsg = "extra compressed data";
1510 :
1511 : /* But otherwise allow extra data: */
1512 0 : else if (size == 0)
1513 : {
1514 0 : if (length > 0)
1515 : {
1516 : /* This can be handled completely, so
1517 : * keep going.
1518 : */
1519 0 : png_chunk_warning(png_ptr,
1520 : "extra compressed data");
1521 : }
1522 :
1523 0 : png_crc_finish(png_ptr, length);
1524 0 : finished = 1;
1525 :
1526 : # if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
1527 : /* Check for a match against sRGB */
1528 : png_icc_set_sRGB(png_ptr,
1529 : &png_ptr->colorspace, profile,
1530 : png_ptr->zstream.adler);
1531 : # endif
1532 :
1533 : /* Steal the profile for info_ptr. */
1534 0 : if (info_ptr != NULL)
1535 : {
1536 0 : png_free_data(png_ptr, info_ptr,
1537 : PNG_FREE_ICCP, 0);
1538 :
1539 0 : info_ptr->iccp_name = png_voidcast(char*,
1540 : png_malloc_base(png_ptr,
1541 : keyword_length+1));
1542 0 : if (info_ptr->iccp_name != NULL)
1543 : {
1544 0 : memcpy(info_ptr->iccp_name, keyword,
1545 0 : keyword_length+1);
1546 0 : info_ptr->iccp_proflen =
1547 : profile_length;
1548 0 : info_ptr->iccp_profile = profile;
1549 0 : png_ptr->read_buffer = NULL; /*steal*/
1550 0 : info_ptr->free_me |= PNG_FREE_ICCP;
1551 0 : info_ptr->valid |= PNG_INFO_iCCP;
1552 : }
1553 :
1554 : else
1555 : {
1556 0 : png_ptr->colorspace.flags |=
1557 : PNG_COLORSPACE_INVALID;
1558 0 : errmsg = "out of memory";
1559 : }
1560 : }
1561 :
1562 : /* else the profile remains in the read
1563 : * buffer which gets reused for subsequent
1564 : * chunks.
1565 : */
1566 :
1567 0 : if (info_ptr != NULL)
1568 0 : png_colorspace_sync(png_ptr, info_ptr);
1569 :
1570 0 : if (errmsg == NULL)
1571 : {
1572 0 : png_ptr->zowner = 0;
1573 0 : return;
1574 : }
1575 : }
1576 :
1577 0 : else if (size > 0)
1578 0 : errmsg = "truncated";
1579 :
1580 : #ifndef __COVERITY__
1581 : else
1582 0 : errmsg = png_ptr->zstream.msg;
1583 : #endif
1584 : }
1585 :
1586 : /* else png_icc_check_tag_table output an error */
1587 : }
1588 :
1589 : else /* profile truncated */
1590 0 : errmsg = png_ptr->zstream.msg;
1591 : }
1592 :
1593 : else
1594 0 : errmsg = "out of memory";
1595 : }
1596 :
1597 : /* else png_icc_check_header output an error */
1598 : }
1599 :
1600 : /* else png_icc_check_length output an error */
1601 : }
1602 :
1603 : else /* profile truncated */
1604 0 : errmsg = png_ptr->zstream.msg;
1605 :
1606 : /* Release the stream */
1607 0 : png_ptr->zowner = 0;
1608 : }
1609 :
1610 : else /* png_inflate_claim failed */
1611 0 : errmsg = png_ptr->zstream.msg;
1612 : }
1613 :
1614 : else
1615 0 : errmsg = "bad compression method"; /* or missing */
1616 : }
1617 :
1618 : else
1619 0 : errmsg = "bad keyword";
1620 : }
1621 :
1622 : else
1623 0 : errmsg = "too many profiles";
1624 :
1625 : /* Failure: the reason is in 'errmsg' */
1626 0 : if (finished == 0)
1627 0 : png_crc_finish(png_ptr, length);
1628 :
1629 0 : png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1630 0 : png_colorspace_sync(png_ptr, info_ptr);
1631 0 : if (errmsg != NULL) /* else already output */
1632 0 : png_chunk_benign_error(png_ptr, errmsg);
1633 : }
1634 : #endif /* READ_iCCP */
1635 :
1636 : #ifdef PNG_READ_sPLT_SUPPORTED
1637 : void /* PRIVATE */
1638 : png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1639 : /* Note: this does not properly handle chunks that are > 64K under DOS */
1640 : {
1641 : png_bytep entry_start, buffer;
1642 : png_sPLT_t new_palette;
1643 : png_sPLT_entryp pp;
1644 : png_uint_32 data_length;
1645 : int entry_size, i;
1646 : png_uint_32 skip = 0;
1647 : png_uint_32 dl;
1648 : png_size_t max_dl;
1649 :
1650 : png_debug(1, "in png_handle_sPLT");
1651 :
1652 : #ifdef PNG_USER_LIMITS_SUPPORTED
1653 : if (png_ptr->user_chunk_cache_max != 0)
1654 : {
1655 : if (png_ptr->user_chunk_cache_max == 1)
1656 : {
1657 : png_crc_finish(png_ptr, length);
1658 : return;
1659 : }
1660 :
1661 : if (--png_ptr->user_chunk_cache_max == 1)
1662 : {
1663 : png_warning(png_ptr, "No space in chunk cache for sPLT");
1664 : png_crc_finish(png_ptr, length);
1665 : return;
1666 : }
1667 : }
1668 : #endif
1669 :
1670 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1671 : png_chunk_error(png_ptr, "missing IHDR");
1672 :
1673 : else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1674 : {
1675 : png_crc_finish(png_ptr, length);
1676 : png_chunk_benign_error(png_ptr, "out of place");
1677 : return;
1678 : }
1679 :
1680 : #ifdef PNG_MAX_MALLOC_64K
1681 : if (length > 65535U)
1682 : {
1683 : png_crc_finish(png_ptr, length);
1684 : png_chunk_benign_error(png_ptr, "too large to fit in memory");
1685 : return;
1686 : }
1687 : #endif
1688 :
1689 : buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
1690 : if (buffer == NULL)
1691 : {
1692 : png_crc_finish(png_ptr, length);
1693 : png_chunk_benign_error(png_ptr, "out of memory");
1694 : return;
1695 : }
1696 :
1697 :
1698 : /* WARNING: this may break if size_t is less than 32 bits; it is assumed
1699 : * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1700 : * potential breakage point if the types in pngconf.h aren't exactly right.
1701 : */
1702 : png_crc_read(png_ptr, buffer, length);
1703 :
1704 : if (png_crc_finish(png_ptr, skip) != 0)
1705 : return;
1706 :
1707 : buffer[length] = 0;
1708 :
1709 : for (entry_start = buffer; *entry_start; entry_start++)
1710 : /* Empty loop to find end of name */ ;
1711 :
1712 : ++entry_start;
1713 :
1714 : /* A sample depth should follow the separator, and we should be on it */
1715 : if (length < 2U || entry_start > buffer + (length - 2U))
1716 : {
1717 : png_warning(png_ptr, "malformed sPLT chunk");
1718 : return;
1719 : }
1720 :
1721 : new_palette.depth = *entry_start++;
1722 : entry_size = (new_palette.depth == 8 ? 6 : 10);
1723 : /* This must fit in a png_uint_32 because it is derived from the original
1724 : * chunk data length.
1725 : */
1726 : data_length = length - (png_uint_32)(entry_start - buffer);
1727 :
1728 : /* Integrity-check the data length */
1729 : if ((data_length % (unsigned int)entry_size) != 0)
1730 : {
1731 : png_warning(png_ptr, "sPLT chunk has bad length");
1732 : return;
1733 : }
1734 :
1735 : dl = (png_uint_32)(data_length / (unsigned int)entry_size);
1736 : max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));
1737 :
1738 : if (dl > max_dl)
1739 : {
1740 : png_warning(png_ptr, "sPLT chunk too long");
1741 : return;
1742 : }
1743 :
1744 : new_palette.nentries = (png_int_32)(data_length / (unsigned int)entry_size);
1745 :
1746 : new_palette.entries = (png_sPLT_entryp)png_malloc_warn(png_ptr,
1747 : (png_alloc_size_t) new_palette.nentries * (sizeof (png_sPLT_entry)));
1748 :
1749 : if (new_palette.entries == NULL)
1750 : {
1751 : png_warning(png_ptr, "sPLT chunk requires too much memory");
1752 : return;
1753 : }
1754 :
1755 : #ifdef PNG_POINTER_INDEXING_SUPPORTED
1756 : for (i = 0; i < new_palette.nentries; i++)
1757 : {
1758 : pp = new_palette.entries + i;
1759 :
1760 : if (new_palette.depth == 8)
1761 : {
1762 : pp->red = *entry_start++;
1763 : pp->green = *entry_start++;
1764 : pp->blue = *entry_start++;
1765 : pp->alpha = *entry_start++;
1766 : }
1767 :
1768 : else
1769 : {
1770 : pp->red = png_get_uint_16(entry_start); entry_start += 2;
1771 : pp->green = png_get_uint_16(entry_start); entry_start += 2;
1772 : pp->blue = png_get_uint_16(entry_start); entry_start += 2;
1773 : pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
1774 : }
1775 :
1776 : pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
1777 : }
1778 : #else
1779 : pp = new_palette.entries;
1780 :
1781 : for (i = 0; i < new_palette.nentries; i++)
1782 : {
1783 :
1784 : if (new_palette.depth == 8)
1785 : {
1786 : pp[i].red = *entry_start++;
1787 : pp[i].green = *entry_start++;
1788 : pp[i].blue = *entry_start++;
1789 : pp[i].alpha = *entry_start++;
1790 : }
1791 :
1792 : else
1793 : {
1794 : pp[i].red = png_get_uint_16(entry_start); entry_start += 2;
1795 : pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
1796 : pp[i].blue = png_get_uint_16(entry_start); entry_start += 2;
1797 : pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
1798 : }
1799 :
1800 : pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
1801 : }
1802 : #endif
1803 :
1804 : /* Discard all chunk data except the name and stash that */
1805 : new_palette.name = (png_charp)buffer;
1806 :
1807 : png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
1808 :
1809 : png_free(png_ptr, new_palette.entries);
1810 : }
1811 : #endif /* READ_sPLT */
1812 :
1813 : #ifdef PNG_READ_tRNS_SUPPORTED
1814 : void /* PRIVATE */
1815 2 : png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1816 : {
1817 : png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
1818 :
1819 : png_debug(1, "in png_handle_tRNS");
1820 :
1821 2 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1822 0 : png_chunk_error(png_ptr, "missing IHDR");
1823 :
1824 2 : else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1825 : {
1826 0 : png_crc_finish(png_ptr, length);
1827 0 : png_chunk_benign_error(png_ptr, "out of place");
1828 0 : return;
1829 : }
1830 :
1831 2 : else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)
1832 : {
1833 0 : png_crc_finish(png_ptr, length);
1834 0 : png_chunk_benign_error(png_ptr, "duplicate");
1835 0 : return;
1836 : }
1837 :
1838 2 : if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
1839 : {
1840 : png_byte buf[2];
1841 :
1842 0 : if (length != 2)
1843 : {
1844 0 : png_crc_finish(png_ptr, length);
1845 0 : png_chunk_benign_error(png_ptr, "invalid");
1846 0 : return;
1847 : }
1848 :
1849 0 : png_crc_read(png_ptr, buf, 2);
1850 0 : png_ptr->num_trans = 1;
1851 0 : png_ptr->trans_color.gray = png_get_uint_16(buf);
1852 : }
1853 :
1854 2 : else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
1855 : {
1856 : png_byte buf[6];
1857 :
1858 0 : if (length != 6)
1859 : {
1860 0 : png_crc_finish(png_ptr, length);
1861 0 : png_chunk_benign_error(png_ptr, "invalid");
1862 0 : return;
1863 : }
1864 :
1865 0 : png_crc_read(png_ptr, buf, length);
1866 0 : png_ptr->num_trans = 1;
1867 0 : png_ptr->trans_color.red = png_get_uint_16(buf);
1868 0 : png_ptr->trans_color.green = png_get_uint_16(buf + 2);
1869 0 : png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
1870 : }
1871 :
1872 2 : else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1873 : {
1874 2 : if ((png_ptr->mode & PNG_HAVE_PLTE) == 0)
1875 : {
1876 : /* TODO: is this actually an error in the ISO spec? */
1877 0 : png_crc_finish(png_ptr, length);
1878 0 : png_chunk_benign_error(png_ptr, "out of place");
1879 0 : return;
1880 : }
1881 :
1882 2 : if (length > (unsigned int) png_ptr->num_palette ||
1883 2 : length > (unsigned int) PNG_MAX_PALETTE_LENGTH ||
1884 : length == 0)
1885 : {
1886 0 : png_crc_finish(png_ptr, length);
1887 0 : png_chunk_benign_error(png_ptr, "invalid");
1888 0 : return;
1889 : }
1890 :
1891 2 : png_crc_read(png_ptr, readbuf, length);
1892 2 : png_ptr->num_trans = (png_uint_16)length;
1893 : }
1894 :
1895 : else
1896 : {
1897 0 : png_crc_finish(png_ptr, length);
1898 0 : png_chunk_benign_error(png_ptr, "invalid with alpha channel");
1899 0 : return;
1900 : }
1901 :
1902 2 : if (png_crc_finish(png_ptr, 0) != 0)
1903 : {
1904 0 : png_ptr->num_trans = 0;
1905 0 : return;
1906 : }
1907 :
1908 : /* TODO: this is a horrible side effect in the palette case because the
1909 : * png_struct ends up with a pointer to the tRNS buffer owned by the
1910 : * png_info. Fix this.
1911 : */
1912 2 : png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
1913 2 : &(png_ptr->trans_color));
1914 : }
1915 : #endif
1916 :
1917 : #ifdef PNG_READ_bKGD_SUPPORTED
1918 : void /* PRIVATE */
1919 : png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1920 : {
1921 : unsigned int truelen;
1922 : png_byte buf[6];
1923 : png_color_16 background;
1924 :
1925 : png_debug(1, "in png_handle_bKGD");
1926 :
1927 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1928 : png_chunk_error(png_ptr, "missing IHDR");
1929 :
1930 : else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
1931 : (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
1932 : (png_ptr->mode & PNG_HAVE_PLTE) == 0))
1933 : {
1934 : png_crc_finish(png_ptr, length);
1935 : png_chunk_benign_error(png_ptr, "out of place");
1936 : return;
1937 : }
1938 :
1939 : else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1940 : {
1941 : png_crc_finish(png_ptr, length);
1942 : png_chunk_benign_error(png_ptr, "duplicate");
1943 : return;
1944 : }
1945 :
1946 : if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1947 : truelen = 1;
1948 :
1949 : else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
1950 : truelen = 6;
1951 :
1952 : else
1953 : truelen = 2;
1954 :
1955 : if (length != truelen)
1956 : {
1957 : png_crc_finish(png_ptr, length);
1958 : png_chunk_benign_error(png_ptr, "invalid");
1959 : return;
1960 : }
1961 :
1962 : png_crc_read(png_ptr, buf, truelen);
1963 :
1964 : if (png_crc_finish(png_ptr, 0) != 0)
1965 : return;
1966 :
1967 : /* We convert the index value into RGB components so that we can allow
1968 : * arbitrary RGB values for background when we have transparency, and
1969 : * so it is easy to determine the RGB values of the background color
1970 : * from the info_ptr struct.
1971 : */
1972 : if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1973 : {
1974 : background.index = buf[0];
1975 :
1976 : if (info_ptr != NULL && info_ptr->num_palette != 0)
1977 : {
1978 : if (buf[0] >= info_ptr->num_palette)
1979 : {
1980 : png_chunk_benign_error(png_ptr, "invalid index");
1981 : return;
1982 : }
1983 :
1984 : background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
1985 : background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
1986 : background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
1987 : }
1988 :
1989 : else
1990 : background.red = background.green = background.blue = 0;
1991 :
1992 : background.gray = 0;
1993 : }
1994 :
1995 : else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */
1996 : {
1997 : background.index = 0;
1998 : background.red =
1999 : background.green =
2000 : background.blue =
2001 : background.gray = png_get_uint_16(buf);
2002 : }
2003 :
2004 : else
2005 : {
2006 : background.index = 0;
2007 : background.red = png_get_uint_16(buf);
2008 : background.green = png_get_uint_16(buf + 2);
2009 : background.blue = png_get_uint_16(buf + 4);
2010 : background.gray = 0;
2011 : }
2012 :
2013 : png_set_bKGD(png_ptr, info_ptr, &background);
2014 : }
2015 : #endif
2016 :
2017 : #ifdef PNG_READ_hIST_SUPPORTED
2018 : void /* PRIVATE */
2019 : png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2020 : {
2021 : unsigned int num, i;
2022 : png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
2023 :
2024 : png_debug(1, "in png_handle_hIST");
2025 :
2026 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2027 : png_chunk_error(png_ptr, "missing IHDR");
2028 :
2029 : else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
2030 : (png_ptr->mode & PNG_HAVE_PLTE) == 0)
2031 : {
2032 : png_crc_finish(png_ptr, length);
2033 : png_chunk_benign_error(png_ptr, "out of place");
2034 : return;
2035 : }
2036 :
2037 : else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
2038 : {
2039 : png_crc_finish(png_ptr, length);
2040 : png_chunk_benign_error(png_ptr, "duplicate");
2041 : return;
2042 : }
2043 :
2044 : num = length / 2 ;
2045 :
2046 : if (num != (unsigned int) png_ptr->num_palette ||
2047 : num > (unsigned int) PNG_MAX_PALETTE_LENGTH)
2048 : {
2049 : png_crc_finish(png_ptr, length);
2050 : png_chunk_benign_error(png_ptr, "invalid");
2051 : return;
2052 : }
2053 :
2054 : for (i = 0; i < num; i++)
2055 : {
2056 : png_byte buf[2];
2057 :
2058 : png_crc_read(png_ptr, buf, 2);
2059 : readbuf[i] = png_get_uint_16(buf);
2060 : }
2061 :
2062 : if (png_crc_finish(png_ptr, 0) != 0)
2063 : return;
2064 :
2065 : png_set_hIST(png_ptr, info_ptr, readbuf);
2066 : }
2067 : #endif
2068 :
2069 : #ifdef PNG_READ_pHYs_SUPPORTED
2070 : void /* PRIVATE */
2071 : png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2072 : {
2073 : png_byte buf[9];
2074 : png_uint_32 res_x, res_y;
2075 : int unit_type;
2076 :
2077 : png_debug(1, "in png_handle_pHYs");
2078 :
2079 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2080 : png_chunk_error(png_ptr, "missing IHDR");
2081 :
2082 : else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2083 : {
2084 : png_crc_finish(png_ptr, length);
2085 : png_chunk_benign_error(png_ptr, "out of place");
2086 : return;
2087 : }
2088 :
2089 : else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0)
2090 : {
2091 : png_crc_finish(png_ptr, length);
2092 : png_chunk_benign_error(png_ptr, "duplicate");
2093 : return;
2094 : }
2095 :
2096 : if (length != 9)
2097 : {
2098 : png_crc_finish(png_ptr, length);
2099 : png_chunk_benign_error(png_ptr, "invalid");
2100 : return;
2101 : }
2102 :
2103 : png_crc_read(png_ptr, buf, 9);
2104 :
2105 : if (png_crc_finish(png_ptr, 0) != 0)
2106 : return;
2107 :
2108 : res_x = png_get_uint_32(buf);
2109 : res_y = png_get_uint_32(buf + 4);
2110 : unit_type = buf[8];
2111 : png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
2112 : }
2113 : #endif
2114 :
2115 : #ifdef PNG_READ_oFFs_SUPPORTED
2116 : void /* PRIVATE */
2117 : png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2118 : {
2119 : png_byte buf[9];
2120 : png_int_32 offset_x, offset_y;
2121 : int unit_type;
2122 :
2123 : png_debug(1, "in png_handle_oFFs");
2124 :
2125 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2126 : png_chunk_error(png_ptr, "missing IHDR");
2127 :
2128 : else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2129 : {
2130 : png_crc_finish(png_ptr, length);
2131 : png_chunk_benign_error(png_ptr, "out of place");
2132 : return;
2133 : }
2134 :
2135 : else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0)
2136 : {
2137 : png_crc_finish(png_ptr, length);
2138 : png_chunk_benign_error(png_ptr, "duplicate");
2139 : return;
2140 : }
2141 :
2142 : if (length != 9)
2143 : {
2144 : png_crc_finish(png_ptr, length);
2145 : png_chunk_benign_error(png_ptr, "invalid");
2146 : return;
2147 : }
2148 :
2149 : png_crc_read(png_ptr, buf, 9);
2150 :
2151 : if (png_crc_finish(png_ptr, 0) != 0)
2152 : return;
2153 :
2154 : offset_x = png_get_int_32(buf);
2155 : offset_y = png_get_int_32(buf + 4);
2156 : unit_type = buf[8];
2157 : png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
2158 : }
2159 : #endif
2160 :
2161 : #ifdef PNG_READ_pCAL_SUPPORTED
2162 : /* Read the pCAL chunk (described in the PNG Extensions document) */
2163 : void /* PRIVATE */
2164 : png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2165 : {
2166 : png_int_32 X0, X1;
2167 : png_byte type, nparams;
2168 : png_bytep buffer, buf, units, endptr;
2169 : png_charpp params;
2170 : int i;
2171 :
2172 : png_debug(1, "in png_handle_pCAL");
2173 :
2174 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2175 : png_chunk_error(png_ptr, "missing IHDR");
2176 :
2177 : else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2178 : {
2179 : png_crc_finish(png_ptr, length);
2180 : png_chunk_benign_error(png_ptr, "out of place");
2181 : return;
2182 : }
2183 :
2184 : else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0)
2185 : {
2186 : png_crc_finish(png_ptr, length);
2187 : png_chunk_benign_error(png_ptr, "duplicate");
2188 : return;
2189 : }
2190 :
2191 : png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2192 : length + 1);
2193 :
2194 : buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2195 :
2196 : if (buffer == NULL)
2197 : {
2198 : png_crc_finish(png_ptr, length);
2199 : png_chunk_benign_error(png_ptr, "out of memory");
2200 : return;
2201 : }
2202 :
2203 : png_crc_read(png_ptr, buffer, length);
2204 :
2205 : if (png_crc_finish(png_ptr, 0) != 0)
2206 : return;
2207 :
2208 : buffer[length] = 0; /* Null terminate the last string */
2209 :
2210 : png_debug(3, "Finding end of pCAL purpose string");
2211 : for (buf = buffer; *buf; buf++)
2212 : /* Empty loop */ ;
2213 :
2214 : endptr = buffer + length;
2215 :
2216 : /* We need to have at least 12 bytes after the purpose string
2217 : * in order to get the parameter information.
2218 : */
2219 : if (endptr - buf <= 12)
2220 : {
2221 : png_chunk_benign_error(png_ptr, "invalid");
2222 : return;
2223 : }
2224 :
2225 : png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2226 : X0 = png_get_int_32((png_bytep)buf+1);
2227 : X1 = png_get_int_32((png_bytep)buf+5);
2228 : type = buf[9];
2229 : nparams = buf[10];
2230 : units = buf + 11;
2231 :
2232 : png_debug(3, "Checking pCAL equation type and number of parameters");
2233 : /* Check that we have the right number of parameters for known
2234 : * equation types.
2235 : */
2236 : if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
2237 : (type == PNG_EQUATION_BASE_E && nparams != 3) ||
2238 : (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
2239 : (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
2240 : {
2241 : png_chunk_benign_error(png_ptr, "invalid parameter count");
2242 : return;
2243 : }
2244 :
2245 : else if (type >= PNG_EQUATION_LAST)
2246 : {
2247 : png_chunk_benign_error(png_ptr, "unrecognized equation type");
2248 : }
2249 :
2250 : for (buf = units; *buf; buf++)
2251 : /* Empty loop to move past the units string. */ ;
2252 :
2253 : png_debug(3, "Allocating pCAL parameters array");
2254 :
2255 : params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
2256 : nparams * (sizeof (png_charp))));
2257 :
2258 : if (params == NULL)
2259 : {
2260 : png_chunk_benign_error(png_ptr, "out of memory");
2261 : return;
2262 : }
2263 :
2264 : /* Get pointers to the start of each parameter string. */
2265 : for (i = 0; i < nparams; i++)
2266 : {
2267 : buf++; /* Skip the null string terminator from previous parameter. */
2268 :
2269 : png_debug1(3, "Reading pCAL parameter %d", i);
2270 :
2271 : for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++)
2272 : /* Empty loop to move past each parameter string */ ;
2273 :
2274 : /* Make sure we haven't run out of data yet */
2275 : if (buf > endptr)
2276 : {
2277 : png_free(png_ptr, params);
2278 : png_chunk_benign_error(png_ptr, "invalid data");
2279 : return;
2280 : }
2281 : }
2282 :
2283 : png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams,
2284 : (png_charp)units, params);
2285 :
2286 : png_free(png_ptr, params);
2287 : }
2288 : #endif
2289 :
2290 : #ifdef PNG_READ_sCAL_SUPPORTED
2291 : /* Read the sCAL chunk */
2292 : void /* PRIVATE */
2293 : png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2294 : {
2295 : png_bytep buffer;
2296 : png_size_t i;
2297 : int state;
2298 :
2299 : png_debug(1, "in png_handle_sCAL");
2300 :
2301 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2302 : png_chunk_error(png_ptr, "missing IHDR");
2303 :
2304 : else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2305 : {
2306 : png_crc_finish(png_ptr, length);
2307 : png_chunk_benign_error(png_ptr, "out of place");
2308 : return;
2309 : }
2310 :
2311 : else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0)
2312 : {
2313 : png_crc_finish(png_ptr, length);
2314 : png_chunk_benign_error(png_ptr, "duplicate");
2315 : return;
2316 : }
2317 :
2318 : /* Need unit type, width, \0, height: minimum 4 bytes */
2319 : else if (length < 4)
2320 : {
2321 : png_crc_finish(png_ptr, length);
2322 : png_chunk_benign_error(png_ptr, "invalid");
2323 : return;
2324 : }
2325 :
2326 : png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2327 : length + 1);
2328 :
2329 : buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2330 :
2331 : if (buffer == NULL)
2332 : {
2333 : png_chunk_benign_error(png_ptr, "out of memory");
2334 : png_crc_finish(png_ptr, length);
2335 : return;
2336 : }
2337 :
2338 : png_crc_read(png_ptr, buffer, length);
2339 : buffer[length] = 0; /* Null terminate the last string */
2340 :
2341 : if (png_crc_finish(png_ptr, 0) != 0)
2342 : return;
2343 :
2344 : /* Validate the unit. */
2345 : if (buffer[0] != 1 && buffer[0] != 2)
2346 : {
2347 : png_chunk_benign_error(png_ptr, "invalid unit");
2348 : return;
2349 : }
2350 :
2351 : /* Validate the ASCII numbers, need two ASCII numbers separated by
2352 : * a '\0' and they need to fit exactly in the chunk data.
2353 : */
2354 : i = 1;
2355 : state = 0;
2356 :
2357 : if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 ||
2358 : i >= length || buffer[i++] != 0)
2359 : png_chunk_benign_error(png_ptr, "bad width format");
2360 :
2361 : else if (PNG_FP_IS_POSITIVE(state) == 0)
2362 : png_chunk_benign_error(png_ptr, "non-positive width");
2363 :
2364 : else
2365 : {
2366 : png_size_t heighti = i;
2367 :
2368 : state = 0;
2369 : if (png_check_fp_number((png_const_charp)buffer, length,
2370 : &state, &i) == 0 || i != length)
2371 : png_chunk_benign_error(png_ptr, "bad height format");
2372 :
2373 : else if (PNG_FP_IS_POSITIVE(state) == 0)
2374 : png_chunk_benign_error(png_ptr, "non-positive height");
2375 :
2376 : else
2377 : /* This is the (only) success case. */
2378 : png_set_sCAL_s(png_ptr, info_ptr, buffer[0],
2379 : (png_charp)buffer+1, (png_charp)buffer+heighti);
2380 : }
2381 : }
2382 : #endif
2383 :
2384 : #ifdef PNG_READ_tIME_SUPPORTED
2385 : void /* PRIVATE */
2386 : png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2387 : {
2388 : png_byte buf[7];
2389 : png_time mod_time;
2390 :
2391 : png_debug(1, "in png_handle_tIME");
2392 :
2393 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2394 : png_chunk_error(png_ptr, "missing IHDR");
2395 :
2396 : else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0)
2397 : {
2398 : png_crc_finish(png_ptr, length);
2399 : png_chunk_benign_error(png_ptr, "duplicate");
2400 : return;
2401 : }
2402 :
2403 : if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2404 : png_ptr->mode |= PNG_AFTER_IDAT;
2405 :
2406 : if (length != 7)
2407 : {
2408 : png_crc_finish(png_ptr, length);
2409 : png_chunk_benign_error(png_ptr, "invalid");
2410 : return;
2411 : }
2412 :
2413 : png_crc_read(png_ptr, buf, 7);
2414 :
2415 : if (png_crc_finish(png_ptr, 0) != 0)
2416 : return;
2417 :
2418 : mod_time.second = buf[6];
2419 : mod_time.minute = buf[5];
2420 : mod_time.hour = buf[4];
2421 : mod_time.day = buf[3];
2422 : mod_time.month = buf[2];
2423 : mod_time.year = png_get_uint_16(buf);
2424 :
2425 : png_set_tIME(png_ptr, info_ptr, &mod_time);
2426 : }
2427 : #endif
2428 :
2429 : #ifdef PNG_READ_tEXt_SUPPORTED
2430 : /* Note: this does not properly handle chunks that are > 64K under DOS */
2431 : void /* PRIVATE */
2432 : png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2433 : {
2434 : png_text text_info;
2435 : png_bytep buffer;
2436 : png_charp key;
2437 : png_charp text;
2438 : png_uint_32 skip = 0;
2439 :
2440 : png_debug(1, "in png_handle_tEXt");
2441 :
2442 : #ifdef PNG_USER_LIMITS_SUPPORTED
2443 : if (png_ptr->user_chunk_cache_max != 0)
2444 : {
2445 : if (png_ptr->user_chunk_cache_max == 1)
2446 : {
2447 : png_crc_finish(png_ptr, length);
2448 : return;
2449 : }
2450 :
2451 : if (--png_ptr->user_chunk_cache_max == 1)
2452 : {
2453 : png_crc_finish(png_ptr, length);
2454 : png_chunk_benign_error(png_ptr, "no space in chunk cache");
2455 : return;
2456 : }
2457 : }
2458 : #endif
2459 :
2460 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2461 : png_chunk_error(png_ptr, "missing IHDR");
2462 :
2463 : if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2464 : png_ptr->mode |= PNG_AFTER_IDAT;
2465 :
2466 : #ifdef PNG_MAX_MALLOC_64K
2467 : if (length > 65535U)
2468 : {
2469 : png_crc_finish(png_ptr, length);
2470 : png_chunk_benign_error(png_ptr, "too large to fit in memory");
2471 : return;
2472 : }
2473 : #endif
2474 :
2475 : buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2476 :
2477 : if (buffer == NULL)
2478 : {
2479 : png_chunk_benign_error(png_ptr, "out of memory");
2480 : return;
2481 : }
2482 :
2483 : png_crc_read(png_ptr, buffer, length);
2484 :
2485 : if (png_crc_finish(png_ptr, skip) != 0)
2486 : return;
2487 :
2488 : key = (png_charp)buffer;
2489 : key[length] = 0;
2490 :
2491 : for (text = key; *text; text++)
2492 : /* Empty loop to find end of key */ ;
2493 :
2494 : if (text != key + length)
2495 : text++;
2496 :
2497 : text_info.compression = PNG_TEXT_COMPRESSION_NONE;
2498 : text_info.key = key;
2499 : text_info.lang = NULL;
2500 : text_info.lang_key = NULL;
2501 : text_info.itxt_length = 0;
2502 : text_info.text = text;
2503 : text_info.text_length = strlen(text);
2504 :
2505 : if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0)
2506 : png_warning(png_ptr, "Insufficient memory to process text chunk");
2507 : }
2508 : #endif
2509 :
2510 : #ifdef PNG_READ_zTXt_SUPPORTED
2511 : /* Note: this does not correctly handle chunks that are > 64K under DOS */
2512 : void /* PRIVATE */
2513 : png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2514 : {
2515 : png_const_charp errmsg = NULL;
2516 : png_bytep buffer;
2517 : png_uint_32 keyword_length;
2518 :
2519 : png_debug(1, "in png_handle_zTXt");
2520 :
2521 : #ifdef PNG_USER_LIMITS_SUPPORTED
2522 : if (png_ptr->user_chunk_cache_max != 0)
2523 : {
2524 : if (png_ptr->user_chunk_cache_max == 1)
2525 : {
2526 : png_crc_finish(png_ptr, length);
2527 : return;
2528 : }
2529 :
2530 : if (--png_ptr->user_chunk_cache_max == 1)
2531 : {
2532 : png_crc_finish(png_ptr, length);
2533 : png_chunk_benign_error(png_ptr, "no space in chunk cache");
2534 : return;
2535 : }
2536 : }
2537 : #endif
2538 :
2539 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2540 : png_chunk_error(png_ptr, "missing IHDR");
2541 :
2542 : if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2543 : png_ptr->mode |= PNG_AFTER_IDAT;
2544 :
2545 : buffer = png_read_buffer(png_ptr, length, 2/*silent*/);
2546 :
2547 : if (buffer == NULL)
2548 : {
2549 : png_crc_finish(png_ptr, length);
2550 : png_chunk_benign_error(png_ptr, "out of memory");
2551 : return;
2552 : }
2553 :
2554 : png_crc_read(png_ptr, buffer, length);
2555 :
2556 : if (png_crc_finish(png_ptr, 0) != 0)
2557 : return;
2558 :
2559 : /* TODO: also check that the keyword contents match the spec! */
2560 : for (keyword_length = 0;
2561 : keyword_length < length && buffer[keyword_length] != 0;
2562 : ++keyword_length)
2563 : /* Empty loop to find end of name */ ;
2564 :
2565 : if (keyword_length > 79 || keyword_length < 1)
2566 : errmsg = "bad keyword";
2567 :
2568 : /* zTXt must have some LZ data after the keyword, although it may expand to
2569 : * zero bytes; we need a '\0' at the end of the keyword, the compression type
2570 : * then the LZ data:
2571 : */
2572 : else if (keyword_length + 3 > length)
2573 : errmsg = "truncated";
2574 :
2575 : else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE)
2576 : errmsg = "unknown compression type";
2577 :
2578 : else
2579 : {
2580 : png_alloc_size_t uncompressed_length = PNG_SIZE_MAX;
2581 :
2582 : /* TODO: at present png_decompress_chunk imposes a single application
2583 : * level memory limit, this should be split to different values for iCCP
2584 : * and text chunks.
2585 : */
2586 : if (png_decompress_chunk(png_ptr, length, keyword_length+2,
2587 : &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2588 : {
2589 : png_text text;
2590 :
2591 : /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except
2592 : * for the extra compression type byte and the fact that it isn't
2593 : * necessarily '\0' terminated.
2594 : */
2595 : buffer = png_ptr->read_buffer;
2596 : buffer[uncompressed_length+(keyword_length+2)] = 0;
2597 :
2598 : text.compression = PNG_TEXT_COMPRESSION_zTXt;
2599 : text.key = (png_charp)buffer;
2600 : text.text = (png_charp)(buffer + keyword_length+2);
2601 : text.text_length = uncompressed_length;
2602 : text.itxt_length = 0;
2603 : text.lang = NULL;
2604 : text.lang_key = NULL;
2605 :
2606 : if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2607 : errmsg = "insufficient memory";
2608 : }
2609 :
2610 : else
2611 : errmsg = png_ptr->zstream.msg;
2612 : }
2613 :
2614 : if (errmsg != NULL)
2615 : png_chunk_benign_error(png_ptr, errmsg);
2616 : }
2617 : #endif
2618 :
2619 : #ifdef PNG_READ_iTXt_SUPPORTED
2620 : /* Note: this does not correctly handle chunks that are > 64K under DOS */
2621 : void /* PRIVATE */
2622 : png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2623 : {
2624 : png_const_charp errmsg = NULL;
2625 : png_bytep buffer;
2626 : png_uint_32 prefix_length;
2627 :
2628 : png_debug(1, "in png_handle_iTXt");
2629 :
2630 : #ifdef PNG_USER_LIMITS_SUPPORTED
2631 : if (png_ptr->user_chunk_cache_max != 0)
2632 : {
2633 : if (png_ptr->user_chunk_cache_max == 1)
2634 : {
2635 : png_crc_finish(png_ptr, length);
2636 : return;
2637 : }
2638 :
2639 : if (--png_ptr->user_chunk_cache_max == 1)
2640 : {
2641 : png_crc_finish(png_ptr, length);
2642 : png_chunk_benign_error(png_ptr, "no space in chunk cache");
2643 : return;
2644 : }
2645 : }
2646 : #endif
2647 :
2648 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2649 : png_chunk_error(png_ptr, "missing IHDR");
2650 :
2651 : if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2652 : png_ptr->mode |= PNG_AFTER_IDAT;
2653 :
2654 : buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2655 :
2656 : if (buffer == NULL)
2657 : {
2658 : png_crc_finish(png_ptr, length);
2659 : png_chunk_benign_error(png_ptr, "out of memory");
2660 : return;
2661 : }
2662 :
2663 : png_crc_read(png_ptr, buffer, length);
2664 :
2665 : if (png_crc_finish(png_ptr, 0) != 0)
2666 : return;
2667 :
2668 : /* First the keyword. */
2669 : for (prefix_length=0;
2670 : prefix_length < length && buffer[prefix_length] != 0;
2671 : ++prefix_length)
2672 : /* Empty loop */ ;
2673 :
2674 : /* Perform a basic check on the keyword length here. */
2675 : if (prefix_length > 79 || prefix_length < 1)
2676 : errmsg = "bad keyword";
2677 :
2678 : /* Expect keyword, compression flag, compression type, language, translated
2679 : * keyword (both may be empty but are 0 terminated) then the text, which may
2680 : * be empty.
2681 : */
2682 : else if (prefix_length + 5 > length)
2683 : errmsg = "truncated";
2684 :
2685 : else if (buffer[prefix_length+1] == 0 ||
2686 : (buffer[prefix_length+1] == 1 &&
2687 : buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE))
2688 : {
2689 : int compressed = buffer[prefix_length+1] != 0;
2690 : png_uint_32 language_offset, translated_keyword_offset;
2691 : png_alloc_size_t uncompressed_length = 0;
2692 :
2693 : /* Now the language tag */
2694 : prefix_length += 3;
2695 : language_offset = prefix_length;
2696 :
2697 : for (; prefix_length < length && buffer[prefix_length] != 0;
2698 : ++prefix_length)
2699 : /* Empty loop */ ;
2700 :
2701 : /* WARNING: the length may be invalid here, this is checked below. */
2702 : translated_keyword_offset = ++prefix_length;
2703 :
2704 : for (; prefix_length < length && buffer[prefix_length] != 0;
2705 : ++prefix_length)
2706 : /* Empty loop */ ;
2707 :
2708 : /* prefix_length should now be at the trailing '\0' of the translated
2709 : * keyword, but it may already be over the end. None of this arithmetic
2710 : * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2711 : * systems the available allocation may overflow.
2712 : */
2713 : ++prefix_length;
2714 :
2715 : if (compressed == 0 && prefix_length <= length)
2716 : uncompressed_length = length - prefix_length;
2717 :
2718 : else if (compressed != 0 && prefix_length < length)
2719 : {
2720 : uncompressed_length = PNG_SIZE_MAX;
2721 :
2722 : /* TODO: at present png_decompress_chunk imposes a single application
2723 : * level memory limit, this should be split to different values for
2724 : * iCCP and text chunks.
2725 : */
2726 : if (png_decompress_chunk(png_ptr, length, prefix_length,
2727 : &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2728 : buffer = png_ptr->read_buffer;
2729 :
2730 : else
2731 : errmsg = png_ptr->zstream.msg;
2732 : }
2733 :
2734 : else
2735 : errmsg = "truncated";
2736 :
2737 : if (errmsg == NULL)
2738 : {
2739 : png_text text;
2740 :
2741 : buffer[uncompressed_length+prefix_length] = 0;
2742 :
2743 : if (compressed == 0)
2744 : text.compression = PNG_ITXT_COMPRESSION_NONE;
2745 :
2746 : else
2747 : text.compression = PNG_ITXT_COMPRESSION_zTXt;
2748 :
2749 : text.key = (png_charp)buffer;
2750 : text.lang = (png_charp)buffer + language_offset;
2751 : text.lang_key = (png_charp)buffer + translated_keyword_offset;
2752 : text.text = (png_charp)buffer + prefix_length;
2753 : text.text_length = 0;
2754 : text.itxt_length = uncompressed_length;
2755 :
2756 : if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2757 : errmsg = "insufficient memory";
2758 : }
2759 : }
2760 :
2761 : else
2762 : errmsg = "bad compression info";
2763 :
2764 : if (errmsg != NULL)
2765 : png_chunk_benign_error(png_ptr, errmsg);
2766 : }
2767 : #endif
2768 :
2769 : #ifdef PNG_READ_APNG_SUPPORTED
2770 : void /* PRIVATE */
2771 4 : png_handle_acTL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
2772 : {
2773 : png_byte data[8];
2774 : png_uint_32 num_frames;
2775 : png_uint_32 num_plays;
2776 : png_uint_32 didSet;
2777 :
2778 : png_debug(1, "in png_handle_acTL");
2779 :
2780 4 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2781 : {
2782 0 : png_error(png_ptr, "Missing IHDR before acTL");
2783 : }
2784 4 : else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2785 : {
2786 0 : png_warning(png_ptr, "Invalid acTL after IDAT skipped");
2787 0 : png_crc_finish(png_ptr, length);
2788 0 : return;
2789 : }
2790 4 : else if ((png_ptr->mode & PNG_HAVE_acTL) != 0)
2791 : {
2792 0 : png_warning(png_ptr, "Duplicate acTL skipped");
2793 0 : png_crc_finish(png_ptr, length);
2794 0 : return;
2795 : }
2796 4 : else if (length != 8)
2797 : {
2798 0 : png_warning(png_ptr, "acTL with invalid length skipped");
2799 0 : png_crc_finish(png_ptr, length);
2800 0 : return;
2801 : }
2802 :
2803 4 : png_crc_read(png_ptr, data, 8);
2804 4 : png_crc_finish(png_ptr, 0);
2805 :
2806 4 : num_frames = png_get_uint_31(png_ptr, data);
2807 4 : num_plays = png_get_uint_31(png_ptr, data + 4);
2808 :
2809 : /* the set function will do error checking on num_frames */
2810 4 : didSet = png_set_acTL(png_ptr, info_ptr, num_frames, num_plays);
2811 4 : if (didSet != 0)
2812 4 : png_ptr->mode |= PNG_HAVE_acTL;
2813 : }
2814 :
2815 : void /* PRIVATE */
2816 38 : png_handle_fcTL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
2817 : {
2818 : png_byte data[22];
2819 : png_uint_32 width;
2820 : png_uint_32 height;
2821 : png_uint_32 x_offset;
2822 : png_uint_32 y_offset;
2823 : png_uint_16 delay_num;
2824 : png_uint_16 delay_den;
2825 : png_byte dispose_op;
2826 : png_byte blend_op;
2827 :
2828 : png_debug(1, "in png_handle_fcTL");
2829 :
2830 38 : png_ensure_sequence_number(png_ptr, length);
2831 :
2832 38 : if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2833 : {
2834 0 : png_error(png_ptr, "Missing IHDR before fcTL");
2835 : }
2836 38 : else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2837 : {
2838 : /* for any frames other then the first this message may be misleading,
2839 : * but correct. PNG_HAVE_IDAT is unset before the frame head is read
2840 : * i can't think of a better message */
2841 0 : png_warning(png_ptr, "Invalid fcTL after IDAT skipped");
2842 0 : png_crc_finish(png_ptr, length-4);
2843 0 : return;
2844 : }
2845 38 : else if ((png_ptr->mode & PNG_HAVE_fcTL) != 0)
2846 : {
2847 0 : png_warning(png_ptr, "Duplicate fcTL within one frame skipped");
2848 0 : png_crc_finish(png_ptr, length-4);
2849 0 : return;
2850 : }
2851 38 : else if (length != 26)
2852 : {
2853 0 : png_warning(png_ptr, "fcTL with invalid length skipped");
2854 0 : png_crc_finish(png_ptr, length-4);
2855 0 : return;
2856 : }
2857 :
2858 38 : png_crc_read(png_ptr, data, 22);
2859 38 : png_crc_finish(png_ptr, 0);
2860 :
2861 38 : width = png_get_uint_31(png_ptr, data);
2862 38 : height = png_get_uint_31(png_ptr, data + 4);
2863 38 : x_offset = png_get_uint_31(png_ptr, data + 8);
2864 38 : y_offset = png_get_uint_31(png_ptr, data + 12);
2865 38 : delay_num = png_get_uint_16(data + 16);
2866 38 : delay_den = png_get_uint_16(data + 18);
2867 38 : dispose_op = data[20];
2868 38 : blend_op = data[21];
2869 :
2870 38 : if (png_ptr->num_frames_read == 0 && (x_offset != 0 || y_offset != 0))
2871 : {
2872 0 : png_warning(png_ptr, "fcTL for the first frame must have zero offset");
2873 0 : return;
2874 : }
2875 :
2876 38 : if (info_ptr != NULL)
2877 : {
2878 42 : if (png_ptr->num_frames_read == 0 &&
2879 8 : (width != info_ptr->width || height != info_ptr->height))
2880 : {
2881 0 : png_warning(png_ptr, "size in first frame's fcTL must match "
2882 : "the size in IHDR");
2883 0 : return;
2884 : }
2885 :
2886 : /* The set function will do more error checking */
2887 38 : png_set_next_frame_fcTL(png_ptr, info_ptr, width, height,
2888 : x_offset, y_offset, delay_num, delay_den,
2889 : dispose_op, blend_op);
2890 :
2891 38 : png_read_reinit(png_ptr, info_ptr);
2892 :
2893 38 : png_ptr->mode |= PNG_HAVE_fcTL;
2894 : }
2895 : }
2896 :
2897 : void /* PRIVATE */
2898 31 : png_have_info(png_structp png_ptr, png_infop info_ptr)
2899 : {
2900 35 : if ((info_ptr->valid & PNG_INFO_acTL) != 0 &&
2901 4 : (info_ptr->valid & PNG_INFO_fcTL) == 0)
2902 : {
2903 0 : png_ptr->apng_flags |= PNG_FIRST_FRAME_HIDDEN;
2904 0 : info_ptr->num_frames++;
2905 : }
2906 31 : }
2907 :
2908 : void /* PRIVATE */
2909 0 : png_handle_fdAT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
2910 : {
2911 0 : png_ensure_sequence_number(png_ptr, length);
2912 :
2913 : /* This function is only called from png_read_end(), png_read_info(),
2914 : * and png_push_read_chunk() which means that:
2915 : * - the user doesn't want to read this frame
2916 : * - or this is an out-of-place fdAT
2917 : * in either case it is safe to ignore the chunk with a warning */
2918 0 : png_warning(png_ptr, "ignoring fdAT chunk");
2919 0 : png_crc_finish(png_ptr, length - 4);
2920 : PNG_UNUSED(info_ptr)
2921 0 : }
2922 :
2923 : void /* PRIVATE */
2924 72 : png_ensure_sequence_number(png_structp png_ptr, png_uint_32 length)
2925 : {
2926 : png_byte data[4];
2927 : png_uint_32 sequence_number;
2928 :
2929 72 : if (length < 4)
2930 0 : png_error(png_ptr, "invalid fcTL or fdAT chunk found");
2931 :
2932 72 : png_crc_read(png_ptr, data, 4);
2933 72 : sequence_number = png_get_uint_31(png_ptr, data);
2934 :
2935 72 : if (sequence_number != png_ptr->next_seq_num)
2936 0 : png_error(png_ptr, "fcTL or fdAT chunk with out-of-order sequence "
2937 : "number found");
2938 :
2939 72 : png_ptr->next_seq_num++;
2940 72 : }
2941 : #endif /* READ_APNG */
2942 :
2943 : #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2944 : /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
2945 : static int
2946 : png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
2947 : {
2948 : png_alloc_size_t limit = PNG_SIZE_MAX;
2949 :
2950 : if (png_ptr->unknown_chunk.data != NULL)
2951 : {
2952 : png_free(png_ptr, png_ptr->unknown_chunk.data);
2953 : png_ptr->unknown_chunk.data = NULL;
2954 : }
2955 :
2956 : # ifdef PNG_SET_USER_LIMITS_SUPPORTED
2957 : if (png_ptr->user_chunk_malloc_max > 0 &&
2958 : png_ptr->user_chunk_malloc_max < limit)
2959 : limit = png_ptr->user_chunk_malloc_max;
2960 :
2961 : # elif PNG_USER_CHUNK_MALLOC_MAX > 0
2962 : if (PNG_USER_CHUNK_MALLOC_MAX < limit)
2963 : limit = PNG_USER_CHUNK_MALLOC_MAX;
2964 : # endif
2965 :
2966 : if (length <= limit)
2967 : {
2968 : PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
2969 : /* The following is safe because of the PNG_SIZE_MAX init above */
2970 : png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/;
2971 : /* 'mode' is a flag array, only the bottom four bits matter here */
2972 : png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
2973 :
2974 : if (length == 0)
2975 : png_ptr->unknown_chunk.data = NULL;
2976 :
2977 : else
2978 : {
2979 : /* Do a 'warn' here - it is handled below. */
2980 : png_ptr->unknown_chunk.data = png_voidcast(png_bytep,
2981 : png_malloc_warn(png_ptr, length));
2982 : }
2983 : }
2984 :
2985 : if (png_ptr->unknown_chunk.data == NULL && length > 0)
2986 : {
2987 : /* This is benign because we clean up correctly */
2988 : png_crc_finish(png_ptr, length);
2989 : png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits");
2990 : return 0;
2991 : }
2992 :
2993 : else
2994 : {
2995 : if (length > 0)
2996 : png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
2997 : png_crc_finish(png_ptr, 0);
2998 : return 1;
2999 : }
3000 : }
3001 : #endif /* READ_UNKNOWN_CHUNKS */
3002 :
3003 : /* Handle an unknown, or known but disabled, chunk */
3004 : void /* PRIVATE */
3005 43 : png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
3006 : png_uint_32 length, int keep)
3007 : {
3008 43 : int handled = 0; /* the chunk was handled */
3009 :
3010 : png_debug(1, "in png_handle_unknown");
3011 :
3012 : #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
3013 : /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
3014 : * the bug which meant that setting a non-default behavior for a specific
3015 : * chunk would be ignored (the default was always used unless a user
3016 : * callback was installed).
3017 : *
3018 : * 'keep' is the value from the png_chunk_unknown_handling, the setting for
3019 : * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
3020 : * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
3021 : * This is just an optimization to avoid multiple calls to the lookup
3022 : * function.
3023 : */
3024 : # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
3025 : # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
3026 : keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
3027 : # endif
3028 : # endif
3029 :
3030 : /* One of the following methods will read the chunk or skip it (at least one
3031 : * of these is always defined because this is the only way to switch on
3032 : * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
3033 : */
3034 : # ifdef PNG_READ_USER_CHUNKS_SUPPORTED
3035 : /* The user callback takes precedence over the chunk keep value, but the
3036 : * keep value is still required to validate a save of a critical chunk.
3037 : */
3038 : if (png_ptr->read_user_chunk_fn != NULL)
3039 : {
3040 : if (png_cache_unknown_chunk(png_ptr, length) != 0)
3041 : {
3042 : /* Callback to user unknown chunk handler */
3043 : int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
3044 : &png_ptr->unknown_chunk);
3045 :
3046 : /* ret is:
3047 : * negative: An error occurred; png_chunk_error will be called.
3048 : * zero: The chunk was not handled, the chunk will be discarded
3049 : * unless png_set_keep_unknown_chunks has been used to set
3050 : * a 'keep' behavior for this particular chunk, in which
3051 : * case that will be used. A critical chunk will cause an
3052 : * error at this point unless it is to be saved.
3053 : * positive: The chunk was handled, libpng will ignore/discard it.
3054 : */
3055 : if (ret < 0)
3056 : png_chunk_error(png_ptr, "error in user chunk");
3057 :
3058 : else if (ret == 0)
3059 : {
3060 : /* If the keep value is 'default' or 'never' override it, but
3061 : * still error out on critical chunks unless the keep value is
3062 : * 'always' While this is weird it is the behavior in 1.4.12.
3063 : * A possible improvement would be to obey the value set for the
3064 : * chunk, but this would be an API change that would probably
3065 : * damage some applications.
3066 : *
3067 : * The png_app_warning below catches the case that matters, where
3068 : * the application has not set specific save or ignore for this
3069 : * chunk or global save or ignore.
3070 : */
3071 : if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
3072 : {
3073 : # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
3074 : if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
3075 : {
3076 : png_chunk_warning(png_ptr, "Saving unknown chunk:");
3077 : png_app_warning(png_ptr,
3078 : "forcing save of an unhandled chunk;"
3079 : " please call png_set_keep_unknown_chunks");
3080 : /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
3081 : }
3082 : # endif
3083 : keep = PNG_HANDLE_CHUNK_IF_SAFE;
3084 : }
3085 : }
3086 :
3087 : else /* chunk was handled */
3088 : {
3089 : handled = 1;
3090 : /* Critical chunks can be safely discarded at this point. */
3091 : keep = PNG_HANDLE_CHUNK_NEVER;
3092 : }
3093 : }
3094 :
3095 : else
3096 : keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
3097 : }
3098 :
3099 : else
3100 : /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
3101 : # endif /* READ_USER_CHUNKS */
3102 :
3103 : # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
3104 : {
3105 : /* keep is currently just the per-chunk setting, if there was no
3106 : * setting change it to the global default now (not that this may
3107 : * still be AS_DEFAULT) then obtain the cache of the chunk if required,
3108 : * if not simply skip the chunk.
3109 : */
3110 : if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
3111 : keep = png_ptr->unknown_default;
3112 :
3113 : if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
3114 : (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
3115 : PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
3116 : {
3117 : if (png_cache_unknown_chunk(png_ptr, length) == 0)
3118 : keep = PNG_HANDLE_CHUNK_NEVER;
3119 : }
3120 :
3121 : else
3122 : png_crc_finish(png_ptr, length);
3123 : }
3124 : # else
3125 : # ifndef PNG_READ_USER_CHUNKS_SUPPORTED
3126 : # error no method to support READ_UNKNOWN_CHUNKS
3127 : # endif
3128 :
3129 : {
3130 : /* If here there is no read callback pointer set and no support is
3131 : * compiled in to just save the unknown chunks, so simply skip this
3132 : * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
3133 : * the app has erroneously asked for unknown chunk saving when there
3134 : * is no support.
3135 : */
3136 : if (keep > PNG_HANDLE_CHUNK_NEVER)
3137 : png_app_error(png_ptr, "no unknown chunk support available");
3138 :
3139 : png_crc_finish(png_ptr, length);
3140 : }
3141 : # endif
3142 :
3143 : # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
3144 : /* Now store the chunk in the chunk list if appropriate, and if the limits
3145 : * permit it.
3146 : */
3147 : if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
3148 : (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
3149 : PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
3150 : {
3151 : # ifdef PNG_USER_LIMITS_SUPPORTED
3152 : switch (png_ptr->user_chunk_cache_max)
3153 : {
3154 : case 2:
3155 : png_ptr->user_chunk_cache_max = 1;
3156 : png_chunk_benign_error(png_ptr, "no space in chunk cache");
3157 : /* FALL THROUGH */
3158 : case 1:
3159 : /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
3160 : * chunk being skipped, now there will be a hard error below.
3161 : */
3162 : break;
3163 :
3164 : default: /* not at limit */
3165 : --(png_ptr->user_chunk_cache_max);
3166 : /* FALL THROUGH */
3167 : case 0: /* no limit */
3168 : # endif /* USER_LIMITS */
3169 : /* Here when the limit isn't reached or when limits are compiled
3170 : * out; store the chunk.
3171 : */
3172 : png_set_unknown_chunks(png_ptr, info_ptr,
3173 : &png_ptr->unknown_chunk, 1);
3174 : handled = 1;
3175 : # ifdef PNG_USER_LIMITS_SUPPORTED
3176 : break;
3177 : }
3178 : # endif
3179 : }
3180 : # else /* no store support: the chunk must be handled by the user callback */
3181 : PNG_UNUSED(info_ptr)
3182 : # endif
3183 :
3184 : /* Regardless of the error handling below the cached data (if any) can be
3185 : * freed now. Notice that the data is not freed if there is a png_error, but
3186 : * it will be freed by destroy_read_struct.
3187 : */
3188 : if (png_ptr->unknown_chunk.data != NULL)
3189 : png_free(png_ptr, png_ptr->unknown_chunk.data);
3190 : png_ptr->unknown_chunk.data = NULL;
3191 :
3192 : #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
3193 : /* There is no support to read an unknown chunk, so just skip it. */
3194 43 : png_crc_finish(png_ptr, length);
3195 : PNG_UNUSED(info_ptr)
3196 : PNG_UNUSED(keep)
3197 : #endif /* !READ_UNKNOWN_CHUNKS */
3198 :
3199 : /* Check for unhandled critical chunks */
3200 43 : if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
3201 0 : png_chunk_error(png_ptr, "unhandled critical chunk");
3202 43 : }
3203 :
3204 : /* This function is called to verify that a chunk name is valid.
3205 : * This function can't have the "critical chunk check" incorporated
3206 : * into it, since in the future we will need to be able to call user
3207 : * functions to handle unknown critical chunks after we check that
3208 : * the chunk name itself is valid.
3209 : */
3210 :
3211 : /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
3212 : *
3213 : * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
3214 : */
3215 :
3216 : void /* PRIVATE */
3217 159 : png_check_chunk_name(png_structrp png_ptr, png_uint_32 chunk_name)
3218 : {
3219 : int i;
3220 :
3221 : png_debug(1, "in png_check_chunk_name");
3222 :
3223 795 : for (i=1; i<=4; ++i)
3224 : {
3225 636 : int c = chunk_name & 0xff;
3226 :
3227 636 : if (c < 65 || c > 122 || (c > 90 && c < 97))
3228 0 : png_chunk_error(png_ptr, "invalid chunk type");
3229 :
3230 636 : chunk_name >>= 8;
3231 : }
3232 159 : }
3233 :
3234 : /* Combines the row recently read in with the existing pixels in the row. This
3235 : * routine takes care of alpha and transparency if requested. This routine also
3236 : * handles the two methods of progressive display of interlaced images,
3237 : * depending on the 'display' value; if 'display' is true then the whole row
3238 : * (dp) is filled from the start by replicating the available pixels. If
3239 : * 'display' is false only those pixels present in the pass are filled in.
3240 : */
3241 : void /* PRIVATE */
3242 0 : png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
3243 : {
3244 0 : unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
3245 0 : png_const_bytep sp = png_ptr->row_buf + 1;
3246 0 : png_alloc_size_t row_width = png_ptr->width;
3247 0 : unsigned int pass = png_ptr->pass;
3248 0 : png_bytep end_ptr = 0;
3249 0 : png_byte end_byte = 0;
3250 : unsigned int end_mask;
3251 :
3252 : png_debug(1, "in png_combine_row");
3253 :
3254 : /* Added in 1.5.6: it should not be possible to enter this routine until at
3255 : * least one row has been read from the PNG data and transformed.
3256 : */
3257 0 : if (pixel_depth == 0)
3258 0 : png_error(png_ptr, "internal row logic error");
3259 :
3260 : /* Added in 1.5.4: the pixel depth should match the information returned by
3261 : * any call to png_read_update_info at this point. Do not continue if we got
3262 : * this wrong.
3263 : */
3264 0 : if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
3265 0 : PNG_ROWBYTES(pixel_depth, row_width))
3266 0 : png_error(png_ptr, "internal row size calculation error");
3267 :
3268 : /* Don't expect this to ever happen: */
3269 0 : if (row_width == 0)
3270 0 : png_error(png_ptr, "internal row width error");
3271 :
3272 : /* Preserve the last byte in cases where only part of it will be overwritten,
3273 : * the multiply below may overflow, we don't care because ANSI-C guarantees
3274 : * we get the low bits.
3275 : */
3276 0 : end_mask = (pixel_depth * row_width) & 7;
3277 0 : if (end_mask != 0)
3278 : {
3279 : /* end_ptr == NULL is a flag to say do nothing */
3280 0 : end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
3281 0 : end_byte = *end_ptr;
3282 : # ifdef PNG_READ_PACKSWAP_SUPPORTED
3283 : if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
3284 : /* little-endian byte */
3285 : end_mask = (unsigned int)(0xff << end_mask);
3286 :
3287 : else /* big-endian byte */
3288 : # endif
3289 0 : end_mask = 0xff >> end_mask;
3290 : /* end_mask is now the bits to *keep* from the destination row */
3291 : }
3292 :
3293 : /* For non-interlaced images this reduces to a memcpy(). A memcpy()
3294 : * will also happen if interlacing isn't supported or if the application
3295 : * does not call png_set_interlace_handling(). In the latter cases the
3296 : * caller just gets a sequence of the unexpanded rows from each interlace
3297 : * pass.
3298 : */
3299 : #ifdef PNG_READ_INTERLACING_SUPPORTED
3300 0 : if (png_ptr->interlaced != 0 &&
3301 0 : (png_ptr->transformations & PNG_INTERLACE) != 0 &&
3302 0 : pass < 6 && (display == 0 ||
3303 : /* The following copies everything for 'display' on passes 0, 2 and 4. */
3304 0 : (display == 1 && (pass & 1) != 0)))
3305 : {
3306 : /* Narrow images may have no bits in a pass; the caller should handle
3307 : * this, but this test is cheap:
3308 : */
3309 0 : if (row_width <= PNG_PASS_START_COL(pass))
3310 0 : return;
3311 :
3312 0 : if (pixel_depth < 8)
3313 : {
3314 : /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3315 : * into 32 bits, then a single loop over the bytes using the four byte
3316 : * values in the 32-bit mask can be used. For the 'display' option the
3317 : * expanded mask may also not require any masking within a byte. To
3318 : * make this work the PACKSWAP option must be taken into account - it
3319 : * simply requires the pixels to be reversed in each byte.
3320 : *
3321 : * The 'regular' case requires a mask for each of the first 6 passes,
3322 : * the 'display' case does a copy for the even passes in the range
3323 : * 0..6. This has already been handled in the test above.
3324 : *
3325 : * The masks are arranged as four bytes with the first byte to use in
3326 : * the lowest bits (little-endian) regardless of the order (PACKSWAP or
3327 : * not) of the pixels in each byte.
3328 : *
3329 : * NOTE: the whole of this logic depends on the caller of this function
3330 : * only calling it on rows appropriate to the pass. This function only
3331 : * understands the 'x' logic; the 'y' logic is handled by the caller.
3332 : *
3333 : * The following defines allow generation of compile time constant bit
3334 : * masks for each pixel depth and each possibility of swapped or not
3335 : * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3336 : * is in the range 0..7; and the result is 1 if the pixel is to be
3337 : * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3338 : * for the block method.
3339 : *
3340 : * With some compilers a compile time expression of the general form:
3341 : *
3342 : * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3343 : *
3344 : * Produces warnings with values of 'shift' in the range 33 to 63
3345 : * because the right hand side of the ?: expression is evaluated by
3346 : * the compiler even though it isn't used. Microsoft Visual C (various
3347 : * versions) and the Intel C compiler are known to do this. To avoid
3348 : * this the following macros are used in 1.5.6. This is a temporary
3349 : * solution to avoid destabilizing the code during the release process.
3350 : */
3351 : # if PNG_USE_COMPILE_TIME_MASKS
3352 : # define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3353 : # define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3354 : # else
3355 : # define PNG_LSR(x,s) ((x)>>(s))
3356 : # define PNG_LSL(x,s) ((x)<<(s))
3357 : # endif
3358 : # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3359 : PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3360 : # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3361 : PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3362 :
3363 : /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3364 : * little endian - the first pixel is at bit 0 - however the extra
3365 : * parameter 's' can be set to cause the mask position to be swapped
3366 : * within each byte, to match the PNG format. This is done by XOR of
3367 : * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3368 : */
3369 : # define PIXEL_MASK(p,x,d,s) \
3370 : (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3371 :
3372 : /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3373 : */
3374 : # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3375 : # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3376 :
3377 : /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3378 : * cases the result needs replicating, for the 4-bpp case the above
3379 : * generates a full 32 bits.
3380 : */
3381 : # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3382 :
3383 : # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3384 : S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3385 : S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3386 :
3387 : # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3388 : B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3389 : B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3390 :
3391 : #if PNG_USE_COMPILE_TIME_MASKS
3392 : /* Utility macros to construct all the masks for a depth/swap
3393 : * combination. The 's' parameter says whether the format is PNG
3394 : * (big endian bytes) or not. Only the three odd-numbered passes are
3395 : * required for the display/block algorithm.
3396 : */
3397 : # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3398 : S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3399 :
3400 : # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
3401 :
3402 : # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
3403 :
3404 : /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
3405 : * then pass:
3406 : */
3407 : static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
3408 : {
3409 : /* Little-endian byte masks for PACKSWAP */
3410 : { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
3411 : /* Normal (big-endian byte) masks - PNG format */
3412 : { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
3413 : };
3414 :
3415 : /* display_mask has only three entries for the odd passes, so index by
3416 : * pass>>1.
3417 : */
3418 : static PNG_CONST png_uint_32 display_mask[2][3][3] =
3419 : {
3420 : /* Little-endian byte masks for PACKSWAP */
3421 : { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
3422 : /* Normal (big-endian byte) masks - PNG format */
3423 : { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
3424 : };
3425 :
3426 : # define MASK(pass,depth,display,png)\
3427 : ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
3428 : row_mask[png][DEPTH_INDEX(depth)][pass])
3429 :
3430 : #else /* !PNG_USE_COMPILE_TIME_MASKS */
3431 : /* This is the runtime alternative: it seems unlikely that this will
3432 : * ever be either smaller or faster than the compile time approach.
3433 : */
3434 : # define MASK(pass,depth,display,png)\
3435 : ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
3436 : #endif /* !USE_COMPILE_TIME_MASKS */
3437 :
3438 : /* Use the appropriate mask to copy the required bits. In some cases
3439 : * the byte mask will be 0 or 0xff; optimize these cases. row_width is
3440 : * the number of pixels, but the code copies bytes, so it is necessary
3441 : * to special case the end.
3442 : */
3443 0 : png_uint_32 pixels_per_byte = 8 / pixel_depth;
3444 : png_uint_32 mask;
3445 :
3446 : # ifdef PNG_READ_PACKSWAP_SUPPORTED
3447 : if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
3448 : mask = MASK(pass, pixel_depth, display, 0);
3449 :
3450 : else
3451 : # endif
3452 0 : mask = MASK(pass, pixel_depth, display, 1);
3453 :
3454 : for (;;)
3455 0 : {
3456 : png_uint_32 m;
3457 :
3458 : /* It doesn't matter in the following if png_uint_32 has more than
3459 : * 32 bits because the high bits always match those in m<<24; it is,
3460 : * however, essential to use OR here, not +, because of this.
3461 : */
3462 0 : m = mask;
3463 0 : mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
3464 0 : m &= 0xff;
3465 :
3466 0 : if (m != 0) /* something to copy */
3467 : {
3468 0 : if (m != 0xff)
3469 0 : *dp = (png_byte)((*dp & ~m) | (*sp & m));
3470 : else
3471 0 : *dp = *sp;
3472 : }
3473 :
3474 : /* NOTE: this may overwrite the last byte with garbage if the image
3475 : * is not an exact number of bytes wide; libpng has always done
3476 : * this.
3477 : */
3478 0 : if (row_width <= pixels_per_byte)
3479 0 : break; /* May need to restore part of the last byte */
3480 :
3481 0 : row_width -= pixels_per_byte;
3482 0 : ++dp;
3483 0 : ++sp;
3484 : }
3485 : }
3486 :
3487 : else /* pixel_depth >= 8 */
3488 : {
3489 : unsigned int bytes_to_copy, bytes_to_jump;
3490 :
3491 : /* Validate the depth - it must be a multiple of 8 */
3492 0 : if (pixel_depth & 7)
3493 0 : png_error(png_ptr, "invalid user transform pixel depth");
3494 :
3495 0 : pixel_depth >>= 3; /* now in bytes */
3496 0 : row_width *= pixel_depth;
3497 :
3498 : /* Regardless of pass number the Adam 7 interlace always results in a
3499 : * fixed number of pixels to copy then to skip. There may be a
3500 : * different number of pixels to skip at the start though.
3501 : */
3502 : {
3503 0 : unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
3504 :
3505 0 : row_width -= offset;
3506 0 : dp += offset;
3507 0 : sp += offset;
3508 : }
3509 :
3510 : /* Work out the bytes to copy. */
3511 0 : if (display != 0)
3512 : {
3513 : /* When doing the 'block' algorithm the pixel in the pass gets
3514 : * replicated to adjacent pixels. This is why the even (0,2,4,6)
3515 : * passes are skipped above - the entire expanded row is copied.
3516 : */
3517 0 : bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
3518 :
3519 : /* But don't allow this number to exceed the actual row width. */
3520 0 : if (bytes_to_copy > row_width)
3521 0 : bytes_to_copy = (unsigned int)/*SAFE*/row_width;
3522 : }
3523 :
3524 : else /* normal row; Adam7 only ever gives us one pixel to copy. */
3525 0 : bytes_to_copy = pixel_depth;
3526 :
3527 : /* In Adam7 there is a constant offset between where the pixels go. */
3528 0 : bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
3529 :
3530 : /* And simply copy these bytes. Some optimization is possible here,
3531 : * depending on the value of 'bytes_to_copy'. Special case the low
3532 : * byte counts, which we know to be frequent.
3533 : *
3534 : * Notice that these cases all 'return' rather than 'break' - this
3535 : * avoids an unnecessary test on whether to restore the last byte
3536 : * below.
3537 : */
3538 0 : switch (bytes_to_copy)
3539 : {
3540 : case 1:
3541 : for (;;)
3542 : {
3543 0 : *dp = *sp;
3544 :
3545 0 : if (row_width <= bytes_to_jump)
3546 0 : return;
3547 :
3548 0 : dp += bytes_to_jump;
3549 0 : sp += bytes_to_jump;
3550 0 : row_width -= bytes_to_jump;
3551 : }
3552 :
3553 : case 2:
3554 : /* There is a possibility of a partial copy at the end here; this
3555 : * slows the code down somewhat.
3556 : */
3557 : do
3558 : {
3559 0 : dp[0] = sp[0], dp[1] = sp[1];
3560 :
3561 0 : if (row_width <= bytes_to_jump)
3562 0 : return;
3563 :
3564 0 : sp += bytes_to_jump;
3565 0 : dp += bytes_to_jump;
3566 0 : row_width -= bytes_to_jump;
3567 : }
3568 0 : while (row_width > 1);
3569 :
3570 : /* And there can only be one byte left at this point: */
3571 0 : *dp = *sp;
3572 0 : return;
3573 :
3574 : case 3:
3575 : /* This can only be the RGB case, so each copy is exactly one
3576 : * pixel and it is not necessary to check for a partial copy.
3577 : */
3578 : for (;;)
3579 : {
3580 0 : dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2];
3581 :
3582 0 : if (row_width <= bytes_to_jump)
3583 0 : return;
3584 :
3585 0 : sp += bytes_to_jump;
3586 0 : dp += bytes_to_jump;
3587 0 : row_width -= bytes_to_jump;
3588 : }
3589 :
3590 : default:
3591 : #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
3592 : /* Check for double byte alignment and, if possible, use a
3593 : * 16-bit copy. Don't attempt this for narrow images - ones that
3594 : * are less than an interlace panel wide. Don't attempt it for
3595 : * wide bytes_to_copy either - use the memcpy there.
3596 : */
3597 0 : if (bytes_to_copy < 16 /*else use memcpy*/ &&
3598 0 : png_isaligned(dp, png_uint_16) &&
3599 0 : png_isaligned(sp, png_uint_16) &&
3600 0 : bytes_to_copy % (sizeof (png_uint_16)) == 0 &&
3601 0 : bytes_to_jump % (sizeof (png_uint_16)) == 0)
3602 : {
3603 : /* Everything is aligned for png_uint_16 copies, but try for
3604 : * png_uint_32 first.
3605 : */
3606 0 : if (png_isaligned(dp, png_uint_32) &&
3607 0 : png_isaligned(sp, png_uint_32) &&
3608 0 : bytes_to_copy % (sizeof (png_uint_32)) == 0 &&
3609 0 : bytes_to_jump % (sizeof (png_uint_32)) == 0)
3610 : {
3611 0 : png_uint_32p dp32 = png_aligncast(png_uint_32p,dp);
3612 0 : png_const_uint_32p sp32 = png_aligncastconst(
3613 : png_const_uint_32p, sp);
3614 0 : size_t skip = (bytes_to_jump-bytes_to_copy) /
3615 : (sizeof (png_uint_32));
3616 :
3617 : do
3618 : {
3619 0 : size_t c = bytes_to_copy;
3620 : do
3621 : {
3622 0 : *dp32++ = *sp32++;
3623 0 : c -= (sizeof (png_uint_32));
3624 : }
3625 0 : while (c > 0);
3626 :
3627 0 : if (row_width <= bytes_to_jump)
3628 0 : return;
3629 :
3630 0 : dp32 += skip;
3631 0 : sp32 += skip;
3632 0 : row_width -= bytes_to_jump;
3633 : }
3634 0 : while (bytes_to_copy <= row_width);
3635 :
3636 : /* Get to here when the row_width truncates the final copy.
3637 : * There will be 1-3 bytes left to copy, so don't try the
3638 : * 16-bit loop below.
3639 : */
3640 0 : dp = (png_bytep)dp32;
3641 0 : sp = (png_const_bytep)sp32;
3642 : do
3643 0 : *dp++ = *sp++;
3644 0 : while (--row_width > 0);
3645 0 : return;
3646 : }
3647 :
3648 : /* Else do it in 16-bit quantities, but only if the size is
3649 : * not too large.
3650 : */
3651 : else
3652 : {
3653 0 : png_uint_16p dp16 = png_aligncast(png_uint_16p, dp);
3654 0 : png_const_uint_16p sp16 = png_aligncastconst(
3655 : png_const_uint_16p, sp);
3656 0 : size_t skip = (bytes_to_jump-bytes_to_copy) /
3657 : (sizeof (png_uint_16));
3658 :
3659 : do
3660 : {
3661 0 : size_t c = bytes_to_copy;
3662 : do
3663 : {
3664 0 : *dp16++ = *sp16++;
3665 0 : c -= (sizeof (png_uint_16));
3666 : }
3667 0 : while (c > 0);
3668 :
3669 0 : if (row_width <= bytes_to_jump)
3670 0 : return;
3671 :
3672 0 : dp16 += skip;
3673 0 : sp16 += skip;
3674 0 : row_width -= bytes_to_jump;
3675 : }
3676 0 : while (bytes_to_copy <= row_width);
3677 :
3678 : /* End of row - 1 byte left, bytes_to_copy > row_width: */
3679 0 : dp = (png_bytep)dp16;
3680 0 : sp = (png_const_bytep)sp16;
3681 : do
3682 0 : *dp++ = *sp++;
3683 0 : while (--row_width > 0);
3684 0 : return;
3685 : }
3686 : }
3687 : #endif /* ALIGN_TYPE code */
3688 :
3689 : /* The true default - use a memcpy: */
3690 : for (;;)
3691 : {
3692 0 : memcpy(dp, sp, bytes_to_copy);
3693 :
3694 0 : if (row_width <= bytes_to_jump)
3695 0 : return;
3696 :
3697 0 : sp += bytes_to_jump;
3698 0 : dp += bytes_to_jump;
3699 0 : row_width -= bytes_to_jump;
3700 0 : if (bytes_to_copy > row_width)
3701 0 : bytes_to_copy = (unsigned int)/*SAFE*/row_width;
3702 : }
3703 : }
3704 :
3705 : /* NOT REACHED*/
3706 : } /* pixel_depth >= 8 */
3707 :
3708 : /* Here if pixel_depth < 8 to check 'end_ptr' below. */
3709 : }
3710 : else
3711 : #endif /* READ_INTERLACING */
3712 :
3713 : /* If here then the switch above wasn't used so just memcpy the whole row
3714 : * from the temporary row buffer (notice that this overwrites the end of the
3715 : * destination row if it is a partial byte.)
3716 : */
3717 0 : memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
3718 :
3719 : /* Restore the overwritten bits from the last byte if necessary. */
3720 0 : if (end_ptr != NULL)
3721 0 : *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
3722 : }
3723 :
3724 : #ifdef PNG_READ_INTERLACING_SUPPORTED
3725 : void /* PRIVATE */
3726 0 : png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
3727 : png_uint_32 transformations /* Because these may affect the byte layout */)
3728 : {
3729 : /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
3730 : /* Offset to next interlace block */
3731 : static PNG_CONST unsigned int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
3732 :
3733 : png_debug(1, "in png_do_read_interlace");
3734 0 : if (row != NULL && row_info != NULL)
3735 : {
3736 : png_uint_32 final_width;
3737 :
3738 0 : final_width = row_info->width * png_pass_inc[pass];
3739 :
3740 0 : switch (row_info->pixel_depth)
3741 : {
3742 : case 1:
3743 : {
3744 0 : png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
3745 0 : png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
3746 : unsigned int sshift, dshift;
3747 : unsigned int s_start, s_end;
3748 : int s_inc;
3749 0 : int jstop = (int)png_pass_inc[pass];
3750 : png_byte v;
3751 : png_uint_32 i;
3752 : int j;
3753 :
3754 : #ifdef PNG_READ_PACKSWAP_SUPPORTED
3755 : if ((transformations & PNG_PACKSWAP) != 0)
3756 : {
3757 : sshift = ((row_info->width + 7) & 0x07);
3758 : dshift = ((final_width + 7) & 0x07);
3759 : s_start = 7;
3760 : s_end = 0;
3761 : s_inc = -1;
3762 : }
3763 :
3764 : else
3765 : #endif
3766 : {
3767 0 : sshift = 7 - ((row_info->width + 7) & 0x07);
3768 0 : dshift = 7 - ((final_width + 7) & 0x07);
3769 0 : s_start = 0;
3770 0 : s_end = 7;
3771 0 : s_inc = 1;
3772 : }
3773 :
3774 0 : for (i = 0; i < row_info->width; i++)
3775 : {
3776 0 : v = (png_byte)((*sp >> sshift) & 0x01);
3777 0 : for (j = 0; j < jstop; j++)
3778 : {
3779 0 : unsigned int tmp = *dp & (0x7f7f >> (7 - dshift));
3780 0 : tmp |= (unsigned int)(v << dshift);
3781 0 : *dp = (png_byte)(tmp & 0xff);
3782 :
3783 0 : if (dshift == s_end)
3784 : {
3785 0 : dshift = s_start;
3786 0 : dp--;
3787 : }
3788 :
3789 : else
3790 0 : dshift = (unsigned int)((int)dshift + s_inc);
3791 : }
3792 :
3793 0 : if (sshift == s_end)
3794 : {
3795 0 : sshift = s_start;
3796 0 : sp--;
3797 : }
3798 :
3799 : else
3800 0 : sshift = (unsigned int)((int)sshift + s_inc);
3801 : }
3802 0 : break;
3803 : }
3804 :
3805 : case 2:
3806 : {
3807 0 : png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
3808 0 : png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
3809 : unsigned int sshift, dshift;
3810 : unsigned int s_start, s_end;
3811 : int s_inc;
3812 0 : int jstop = (int)png_pass_inc[pass];
3813 : png_uint_32 i;
3814 :
3815 : #ifdef PNG_READ_PACKSWAP_SUPPORTED
3816 : if ((transformations & PNG_PACKSWAP) != 0)
3817 : {
3818 : sshift = (((row_info->width + 3) & 0x03) << 1);
3819 : dshift = (((final_width + 3) & 0x03) << 1);
3820 : s_start = 6;
3821 : s_end = 0;
3822 : s_inc = -2;
3823 : }
3824 :
3825 : else
3826 : #endif
3827 : {
3828 0 : sshift = ((3 - ((row_info->width + 3) & 0x03)) << 1);
3829 0 : dshift = ((3 - ((final_width + 3) & 0x03)) << 1);
3830 0 : s_start = 0;
3831 0 : s_end = 6;
3832 0 : s_inc = 2;
3833 : }
3834 :
3835 0 : for (i = 0; i < row_info->width; i++)
3836 : {
3837 : png_byte v;
3838 : int j;
3839 :
3840 0 : v = (png_byte)((*sp >> sshift) & 0x03);
3841 0 : for (j = 0; j < jstop; j++)
3842 : {
3843 0 : unsigned int tmp = *dp & (0x3f3f >> (6 - dshift));
3844 0 : tmp |= (unsigned int)(v << dshift);
3845 0 : *dp = (png_byte)(tmp & 0xff);
3846 :
3847 0 : if (dshift == s_end)
3848 : {
3849 0 : dshift = s_start;
3850 0 : dp--;
3851 : }
3852 :
3853 : else
3854 0 : dshift = (unsigned int)((int)dshift + s_inc);
3855 : }
3856 :
3857 0 : if (sshift == s_end)
3858 : {
3859 0 : sshift = s_start;
3860 0 : sp--;
3861 : }
3862 :
3863 : else
3864 0 : sshift = (unsigned int)((int)sshift + s_inc);
3865 : }
3866 0 : break;
3867 : }
3868 :
3869 : case 4:
3870 : {
3871 0 : png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
3872 0 : png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
3873 : unsigned int sshift, dshift;
3874 : unsigned int s_start, s_end;
3875 : int s_inc;
3876 : png_uint_32 i;
3877 0 : int jstop = (int)png_pass_inc[pass];
3878 :
3879 : #ifdef PNG_READ_PACKSWAP_SUPPORTED
3880 : if ((transformations & PNG_PACKSWAP) != 0)
3881 : {
3882 : sshift = (((row_info->width + 1) & 0x01) << 2);
3883 : dshift = (((final_width + 1) & 0x01) << 2);
3884 : s_start = 4;
3885 : s_end = 0;
3886 : s_inc = -4;
3887 : }
3888 :
3889 : else
3890 : #endif
3891 : {
3892 0 : sshift = ((1 - ((row_info->width + 1) & 0x01)) << 2);
3893 0 : dshift = ((1 - ((final_width + 1) & 0x01)) << 2);
3894 0 : s_start = 0;
3895 0 : s_end = 4;
3896 0 : s_inc = 4;
3897 : }
3898 :
3899 0 : for (i = 0; i < row_info->width; i++)
3900 : {
3901 0 : png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
3902 : int j;
3903 :
3904 0 : for (j = 0; j < jstop; j++)
3905 : {
3906 0 : unsigned int tmp = *dp & (0xf0f >> (4 - dshift));
3907 0 : tmp |= (unsigned int)(v << dshift);
3908 0 : *dp = (png_byte)(tmp & 0xff);
3909 :
3910 0 : if (dshift == s_end)
3911 : {
3912 0 : dshift = s_start;
3913 0 : dp--;
3914 : }
3915 :
3916 : else
3917 0 : dshift = (unsigned int)((int)dshift + s_inc);
3918 : }
3919 :
3920 0 : if (sshift == s_end)
3921 : {
3922 0 : sshift = s_start;
3923 0 : sp--;
3924 : }
3925 :
3926 : else
3927 0 : sshift = (unsigned int)((int)sshift + s_inc);
3928 : }
3929 0 : break;
3930 : }
3931 :
3932 : default:
3933 : {
3934 0 : png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
3935 :
3936 0 : png_bytep sp = row + (png_size_t)(row_info->width - 1)
3937 0 : * pixel_bytes;
3938 :
3939 0 : png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;
3940 :
3941 0 : int jstop = (int)png_pass_inc[pass];
3942 : png_uint_32 i;
3943 :
3944 0 : for (i = 0; i < row_info->width; i++)
3945 : {
3946 : png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */
3947 : int j;
3948 :
3949 0 : memcpy(v, sp, pixel_bytes);
3950 :
3951 0 : for (j = 0; j < jstop; j++)
3952 : {
3953 0 : memcpy(dp, v, pixel_bytes);
3954 0 : dp -= pixel_bytes;
3955 : }
3956 :
3957 0 : sp -= pixel_bytes;
3958 : }
3959 0 : break;
3960 : }
3961 : }
3962 :
3963 0 : row_info->width = final_width;
3964 0 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
3965 : }
3966 : #ifndef PNG_READ_PACKSWAP_SUPPORTED
3967 : PNG_UNUSED(transformations) /* Silence compiler warning */
3968 : #endif
3969 0 : }
3970 : #endif /* READ_INTERLACING */
3971 :
3972 : static void
3973 10 : png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
3974 : png_const_bytep prev_row)
3975 : {
3976 : png_size_t i;
3977 10 : png_size_t istop = row_info->rowbytes;
3978 10 : unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
3979 10 : png_bytep rp = row + bpp;
3980 :
3981 : PNG_UNUSED(prev_row)
3982 :
3983 2390 : for (i = bpp; i < istop; i++)
3984 : {
3985 2380 : *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
3986 2380 : rp++;
3987 : }
3988 10 : }
3989 :
3990 : static void
3991 531 : png_read_filter_row_up(png_row_infop row_info, png_bytep row,
3992 : png_const_bytep prev_row)
3993 : {
3994 : png_size_t i;
3995 531 : png_size_t istop = row_info->rowbytes;
3996 531 : png_bytep rp = row;
3997 531 : png_const_bytep pp = prev_row;
3998 :
3999 69871 : for (i = 0; i < istop; i++)
4000 : {
4001 69340 : *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
4002 69340 : rp++;
4003 : }
4004 531 : }
4005 :
4006 : static void
4007 0 : png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
4008 : png_const_bytep prev_row)
4009 : {
4010 : png_size_t i;
4011 0 : png_bytep rp = row;
4012 0 : png_const_bytep pp = prev_row;
4013 0 : unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
4014 0 : png_size_t istop = row_info->rowbytes - bpp;
4015 :
4016 0 : for (i = 0; i < bpp; i++)
4017 : {
4018 0 : *rp = (png_byte)(((int)(*rp) +
4019 0 : ((int)(*pp++) / 2 )) & 0xff);
4020 :
4021 0 : rp++;
4022 : }
4023 :
4024 0 : for (i = 0; i < istop; i++)
4025 : {
4026 0 : *rp = (png_byte)(((int)(*rp) +
4027 0 : (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
4028 :
4029 0 : rp++;
4030 : }
4031 0 : }
4032 :
4033 : static void
4034 0 : png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
4035 : png_const_bytep prev_row)
4036 : {
4037 0 : png_bytep rp_end = row + row_info->rowbytes;
4038 : int a, c;
4039 :
4040 : /* First pixel/byte */
4041 0 : c = *prev_row++;
4042 0 : a = *row + c;
4043 0 : *row++ = (png_byte)a;
4044 :
4045 : /* Remainder */
4046 0 : while (row < rp_end)
4047 : {
4048 : int b, pa, pb, pc, p;
4049 :
4050 0 : a &= 0xff; /* From previous iteration or start */
4051 0 : b = *prev_row++;
4052 :
4053 0 : p = b - c;
4054 0 : pc = a - c;
4055 :
4056 : #ifdef PNG_USE_ABS
4057 : pa = abs(p);
4058 : pb = abs(pc);
4059 : pc = abs(p + pc);
4060 : #else
4061 0 : pa = p < 0 ? -p : p;
4062 0 : pb = pc < 0 ? -pc : pc;
4063 0 : pc = (p + pc) < 0 ? -(p + pc) : p + pc;
4064 : #endif
4065 :
4066 : /* Find the best predictor, the least of pa, pb, pc favoring the earlier
4067 : * ones in the case of a tie.
4068 : */
4069 0 : if (pb < pa) pa = pb, a = b;
4070 0 : if (pc < pa) a = c;
4071 :
4072 : /* Calculate the current pixel in a, and move the previous row pixel to c
4073 : * for the next time round the loop
4074 : */
4075 0 : c = b;
4076 0 : a += *row;
4077 0 : *row++ = (png_byte)a;
4078 : }
4079 0 : }
4080 :
4081 : static void
4082 2 : png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
4083 : png_const_bytep prev_row)
4084 : {
4085 2 : unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
4086 2 : png_bytep rp_end = row + bpp;
4087 :
4088 : /* Process the first pixel in the row completely (this is the same as 'up'
4089 : * because there is only one candidate predictor for the first row).
4090 : */
4091 8 : while (row < rp_end)
4092 : {
4093 4 : int a = *row + *prev_row++;
4094 4 : *row++ = (png_byte)a;
4095 : }
4096 :
4097 : /* Remainder */
4098 2 : rp_end = rp_end + (row_info->rowbytes - bpp);
4099 :
4100 480 : while (row < rp_end)
4101 : {
4102 : int a, b, c, pa, pb, pc, p;
4103 :
4104 476 : c = *(prev_row - bpp);
4105 476 : a = *(row - bpp);
4106 476 : b = *prev_row++;
4107 :
4108 476 : p = b - c;
4109 476 : pc = a - c;
4110 :
4111 : #ifdef PNG_USE_ABS
4112 : pa = abs(p);
4113 : pb = abs(pc);
4114 : pc = abs(p + pc);
4115 : #else
4116 476 : pa = p < 0 ? -p : p;
4117 476 : pb = pc < 0 ? -pc : pc;
4118 476 : pc = (p + pc) < 0 ? -(p + pc) : p + pc;
4119 : #endif
4120 :
4121 476 : if (pb < pa) pa = pb, a = b;
4122 476 : if (pc < pa) a = c;
4123 :
4124 476 : a += *row;
4125 476 : *row++ = (png_byte)a;
4126 : }
4127 2 : }
4128 :
4129 : static void
4130 8 : png_init_filter_functions(png_structrp pp)
4131 : /* This function is called once for every PNG image (except for PNG images
4132 : * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
4133 : * implementations required to reverse the filtering of PNG rows. Reversing
4134 : * the filter is the first transformation performed on the row data. It is
4135 : * performed in place, therefore an implementation can be selected based on
4136 : * the image pixel format. If the implementation depends on image width then
4137 : * take care to ensure that it works correctly if the image is interlaced -
4138 : * interlacing causes the actual row width to vary.
4139 : */
4140 : {
4141 8 : unsigned int bpp = (pp->pixel_depth + 7) >> 3;
4142 :
4143 8 : pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
4144 8 : pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
4145 8 : pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
4146 8 : if (bpp == 1)
4147 0 : pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
4148 : png_read_filter_row_paeth_1byte_pixel;
4149 : else
4150 8 : pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
4151 : png_read_filter_row_paeth_multibyte_pixel;
4152 :
4153 : #ifdef PNG_FILTER_OPTIMIZATIONS
4154 : /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
4155 : * call to install hardware optimizations for the above functions; simply
4156 : * replace whatever elements of the pp->read_filter[] array with a hardware
4157 : * specific (or, for that matter, generic) optimization.
4158 : *
4159 : * To see an example of this examine what configure.ac does when
4160 : * --enable-arm-neon is specified on the command line.
4161 : */
4162 8 : PNG_FILTER_OPTIMIZATIONS(pp, bpp);
4163 : #endif
4164 8 : }
4165 :
4166 : void /* PRIVATE */
4167 1219 : png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row,
4168 : png_const_bytep prev_row, int filter)
4169 : {
4170 : /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
4171 : * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
4172 : * implementations. See png_init_filter_functions above.
4173 : */
4174 1219 : if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
4175 : {
4176 1219 : if (pp->read_filter[0] == NULL)
4177 8 : png_init_filter_functions(pp);
4178 :
4179 1219 : pp->read_filter[filter-1](row_info, row, prev_row);
4180 : }
4181 1219 : }
4182 :
4183 : #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
4184 : void /* PRIVATE */
4185 : png_read_IDAT_data(png_structrp png_ptr, png_bytep output,
4186 : png_alloc_size_t avail_out)
4187 : {
4188 : /* Loop reading IDATs and decompressing the result into output[avail_out] */
4189 : png_ptr->zstream.next_out = output;
4190 : png_ptr->zstream.avail_out = 0; /* safety: set below */
4191 :
4192 : if (output == NULL)
4193 : avail_out = 0;
4194 :
4195 : do
4196 : {
4197 : int ret;
4198 : png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
4199 :
4200 : if (png_ptr->zstream.avail_in == 0)
4201 : {
4202 : uInt avail_in;
4203 : png_bytep buffer;
4204 :
4205 : #ifdef PNG_READ_APNG_SUPPORTED
4206 : png_uint_32 bytes_to_skip = 0;
4207 :
4208 : while (png_ptr->idat_size == 0 || bytes_to_skip != 0)
4209 : {
4210 : png_crc_finish(png_ptr, bytes_to_skip);
4211 : bytes_to_skip = 0;
4212 :
4213 : png_ptr->idat_size = png_read_chunk_header(png_ptr);
4214 : if (png_ptr->num_frames_read == 0)
4215 : {
4216 : if (png_ptr->chunk_name != png_IDAT)
4217 : png_error(png_ptr, "Not enough image data");
4218 : }
4219 : else
4220 : {
4221 : if (png_ptr->chunk_name == png_IEND)
4222 : png_error(png_ptr, "Not enough image data");
4223 : if (png_ptr->chunk_name != png_fdAT)
4224 : {
4225 : png_warning(png_ptr, "Skipped (ignored) a chunk "
4226 : "between APNG chunks");
4227 : bytes_to_skip = png_ptr->idat_size;
4228 : continue;
4229 : }
4230 :
4231 : png_ensure_sequence_number(png_ptr, png_ptr->idat_size);
4232 :
4233 : png_ptr->idat_size -= 4;
4234 : }
4235 : }
4236 : #else
4237 : while (png_ptr->idat_size == 0)
4238 : {
4239 : png_crc_finish(png_ptr, 0);
4240 :
4241 : png_ptr->idat_size = png_read_chunk_header(png_ptr);
4242 : /* This is an error even in the 'check' case because the code just
4243 : * consumed a non-IDAT header.
4244 : */
4245 : if (png_ptr->chunk_name != png_IDAT)
4246 : png_error(png_ptr, "Not enough image data");
4247 : }
4248 : #endif /* READ_APNG */
4249 :
4250 : avail_in = png_ptr->IDAT_read_size;
4251 :
4252 : if (avail_in > png_ptr->idat_size)
4253 : avail_in = (uInt)png_ptr->idat_size;
4254 :
4255 : /* A PNG with a gradually increasing IDAT size will defeat this attempt
4256 : * to minimize memory usage by causing lots of re-allocs, but
4257 : * realistically doing IDAT_read_size re-allocs is not likely to be a
4258 : * big problem.
4259 : */
4260 : buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/);
4261 :
4262 : png_crc_read(png_ptr, buffer, avail_in);
4263 : png_ptr->idat_size -= avail_in;
4264 :
4265 : png_ptr->zstream.next_in = buffer;
4266 : png_ptr->zstream.avail_in = avail_in;
4267 : }
4268 :
4269 : /* And set up the output side. */
4270 : if (output != NULL) /* standard read */
4271 : {
4272 : uInt out = ZLIB_IO_MAX;
4273 :
4274 : if (out > avail_out)
4275 : out = (uInt)avail_out;
4276 :
4277 : avail_out -= out;
4278 : png_ptr->zstream.avail_out = out;
4279 : }
4280 :
4281 : else /* after last row, checking for end */
4282 : {
4283 : png_ptr->zstream.next_out = tmpbuf;
4284 : png_ptr->zstream.avail_out = (sizeof tmpbuf);
4285 : }
4286 :
4287 : /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
4288 : * process. If the LZ stream is truncated the sequential reader will
4289 : * terminally damage the stream, above, by reading the chunk header of the
4290 : * following chunk (it then exits with png_error).
4291 : *
4292 : * TODO: deal more elegantly with truncated IDAT lists.
4293 : */
4294 : ret = PNG_INFLATE(png_ptr, Z_NO_FLUSH);
4295 :
4296 : /* Take the unconsumed output back. */
4297 : if (output != NULL)
4298 : avail_out += png_ptr->zstream.avail_out;
4299 :
4300 : else /* avail_out counts the extra bytes */
4301 : avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out;
4302 :
4303 : png_ptr->zstream.avail_out = 0;
4304 :
4305 : if (ret == Z_STREAM_END)
4306 : {
4307 : /* Do this for safety; we won't read any more into this row. */
4308 : png_ptr->zstream.next_out = NULL;
4309 :
4310 : png_ptr->mode |= PNG_AFTER_IDAT;
4311 : png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4312 : #ifdef PNG_READ_APNG_SUPPORTED
4313 : png_ptr->num_frames_read++;
4314 : #endif
4315 :
4316 : if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0)
4317 : png_chunk_benign_error(png_ptr, "Extra compressed data");
4318 : break;
4319 : }
4320 :
4321 : if (ret != Z_OK)
4322 : {
4323 : png_zstream_error(png_ptr, ret);
4324 :
4325 : if (output != NULL)
4326 : png_chunk_error(png_ptr, png_ptr->zstream.msg);
4327 :
4328 : else /* checking */
4329 : {
4330 : png_chunk_benign_error(png_ptr, png_ptr->zstream.msg);
4331 : return;
4332 : }
4333 : }
4334 : } while (avail_out > 0);
4335 :
4336 : if (avail_out > 0)
4337 : {
4338 : /* The stream ended before the image; this is the same as too few IDATs so
4339 : * should be handled the same way.
4340 : */
4341 : if (output != NULL)
4342 : png_error(png_ptr, "Not enough image data");
4343 :
4344 : else /* the deflate stream contained extra data */
4345 : png_chunk_benign_error(png_ptr, "Too much image data");
4346 : }
4347 : }
4348 :
4349 : void /* PRIVATE */
4350 : png_read_finish_IDAT(png_structrp png_ptr)
4351 : {
4352 : /* We don't need any more data and the stream should have ended, however the
4353 : * LZ end code may actually not have been processed. In this case we must
4354 : * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
4355 : * may still remain to be consumed.
4356 : */
4357 : if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
4358 : {
4359 : /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
4360 : * the compressed stream, but the stream may be damaged too, so even after
4361 : * this call we may need to terminate the zstream ownership.
4362 : */
4363 : png_read_IDAT_data(png_ptr, NULL, 0);
4364 : png_ptr->zstream.next_out = NULL; /* safety */
4365 :
4366 : /* Now clear everything out for safety; the following may not have been
4367 : * done.
4368 : */
4369 : if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
4370 : {
4371 : png_ptr->mode |= PNG_AFTER_IDAT;
4372 : png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4373 : }
4374 : }
4375 :
4376 : /* If the zstream has not been released do it now *and* terminate the reading
4377 : * of the final IDAT chunk.
4378 : */
4379 : if (png_ptr->zowner == png_IDAT)
4380 : {
4381 : /* Always do this; the pointers otherwise point into the read buffer. */
4382 : png_ptr->zstream.next_in = NULL;
4383 : png_ptr->zstream.avail_in = 0;
4384 :
4385 : /* Now we no longer own the zstream. */
4386 : png_ptr->zowner = 0;
4387 :
4388 : /* The slightly weird semantics of the sequential IDAT reading is that we
4389 : * are always in or at the end of an IDAT chunk, so we always need to do a
4390 : * crc_finish here. If idat_size is non-zero we also need to read the
4391 : * spurious bytes at the end of the chunk now.
4392 : */
4393 : (void)png_crc_finish(png_ptr, png_ptr->idat_size);
4394 : }
4395 : }
4396 :
4397 : void /* PRIVATE */
4398 : png_read_finish_row(png_structrp png_ptr)
4399 : {
4400 : /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4401 :
4402 : /* Start of interlace block */
4403 : static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4404 :
4405 : /* Offset to next interlace block */
4406 : static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4407 :
4408 : /* Start of interlace block in the y direction */
4409 : static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4410 :
4411 : /* Offset to next interlace block in the y direction */
4412 : static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4413 :
4414 : png_debug(1, "in png_read_finish_row");
4415 : png_ptr->row_number++;
4416 : if (png_ptr->row_number < png_ptr->num_rows)
4417 : return;
4418 :
4419 : if (png_ptr->interlaced != 0)
4420 : {
4421 : png_ptr->row_number = 0;
4422 :
4423 : /* TO DO: don't do this if prev_row isn't needed (requires
4424 : * read-ahead of the next row's filter byte.
4425 : */
4426 : memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4427 :
4428 : do
4429 : {
4430 : png_ptr->pass++;
4431 :
4432 : if (png_ptr->pass >= 7)
4433 : break;
4434 :
4435 : png_ptr->iwidth = (png_ptr->width +
4436 : png_pass_inc[png_ptr->pass] - 1 -
4437 : png_pass_start[png_ptr->pass]) /
4438 : png_pass_inc[png_ptr->pass];
4439 :
4440 : if ((png_ptr->transformations & PNG_INTERLACE) == 0)
4441 : {
4442 : png_ptr->num_rows = (png_ptr->height +
4443 : png_pass_yinc[png_ptr->pass] - 1 -
4444 : png_pass_ystart[png_ptr->pass]) /
4445 : png_pass_yinc[png_ptr->pass];
4446 : }
4447 :
4448 : else /* if (png_ptr->transformations & PNG_INTERLACE) */
4449 : break; /* libpng deinterlacing sees every row */
4450 :
4451 : } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0);
4452 :
4453 : if (png_ptr->pass < 7)
4454 : return;
4455 : }
4456 :
4457 : /* Here after at the end of the last row of the last pass. */
4458 : png_read_finish_IDAT(png_ptr);
4459 : }
4460 : #endif /* SEQUENTIAL_READ */
4461 :
4462 : void /* PRIVATE */
4463 31 : png_read_start_row(png_structrp png_ptr)
4464 : {
4465 : /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4466 :
4467 : /* Start of interlace block */
4468 : static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4469 :
4470 : /* Offset to next interlace block */
4471 : static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4472 :
4473 : /* Start of interlace block in the y direction */
4474 : static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4475 :
4476 : /* Offset to next interlace block in the y direction */
4477 : static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4478 :
4479 : unsigned int max_pixel_depth;
4480 : png_size_t row_bytes;
4481 :
4482 : png_debug(1, "in png_read_start_row");
4483 :
4484 : #ifdef PNG_READ_TRANSFORMS_SUPPORTED
4485 31 : png_init_read_transformations(png_ptr);
4486 : #endif
4487 31 : if (png_ptr->interlaced != 0)
4488 : {
4489 0 : if ((png_ptr->transformations & PNG_INTERLACE) == 0)
4490 0 : png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
4491 0 : png_pass_ystart[0]) / png_pass_yinc[0];
4492 :
4493 : else
4494 0 : png_ptr->num_rows = png_ptr->height;
4495 :
4496 0 : png_ptr->iwidth = (png_ptr->width +
4497 0 : png_pass_inc[png_ptr->pass] - 1 -
4498 0 : png_pass_start[png_ptr->pass]) /
4499 0 : png_pass_inc[png_ptr->pass];
4500 : }
4501 :
4502 : else
4503 : {
4504 31 : png_ptr->num_rows = png_ptr->height;
4505 31 : png_ptr->iwidth = png_ptr->width;
4506 : }
4507 :
4508 31 : max_pixel_depth = (unsigned int)png_ptr->pixel_depth;
4509 :
4510 : /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
4511 : * calculations to calculate the final pixel depth, then
4512 : * png_do_read_transforms actually does the transforms. This means that the
4513 : * code which effectively calculates this value is actually repeated in three
4514 : * separate places. They must all match. Innocent changes to the order of
4515 : * transformations can and will break libpng in a way that causes memory
4516 : * overwrites.
4517 : *
4518 : * TODO: fix this.
4519 : */
4520 : #ifdef PNG_READ_PACK_SUPPORTED
4521 : if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8)
4522 : max_pixel_depth = 8;
4523 : #endif
4524 :
4525 : #ifdef PNG_READ_EXPAND_SUPPORTED
4526 31 : if ((png_ptr->transformations & PNG_EXPAND) != 0)
4527 : {
4528 31 : if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4529 : {
4530 2 : if (png_ptr->num_trans != 0)
4531 2 : max_pixel_depth = 32;
4532 :
4533 : else
4534 0 : max_pixel_depth = 24;
4535 : }
4536 :
4537 29 : else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4538 : {
4539 0 : if (max_pixel_depth < 8)
4540 0 : max_pixel_depth = 8;
4541 :
4542 0 : if (png_ptr->num_trans != 0)
4543 0 : max_pixel_depth *= 2;
4544 : }
4545 :
4546 29 : else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
4547 : {
4548 0 : if (png_ptr->num_trans != 0)
4549 : {
4550 0 : max_pixel_depth *= 4;
4551 0 : max_pixel_depth /= 3;
4552 : }
4553 : }
4554 : }
4555 : #endif
4556 :
4557 : #ifdef PNG_READ_EXPAND_16_SUPPORTED
4558 : if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
4559 : {
4560 : # ifdef PNG_READ_EXPAND_SUPPORTED
4561 : /* In fact it is an error if it isn't supported, but checking is
4562 : * the safe way.
4563 : */
4564 : if ((png_ptr->transformations & PNG_EXPAND) != 0)
4565 : {
4566 : if (png_ptr->bit_depth < 16)
4567 : max_pixel_depth *= 2;
4568 : }
4569 : else
4570 : # endif
4571 : png_ptr->transformations &= ~PNG_EXPAND_16;
4572 : }
4573 : #endif
4574 :
4575 : #ifdef PNG_READ_FILLER_SUPPORTED
4576 : if ((png_ptr->transformations & (PNG_FILLER)) != 0)
4577 : {
4578 : if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4579 : {
4580 : if (max_pixel_depth <= 8)
4581 : max_pixel_depth = 16;
4582 :
4583 : else
4584 : max_pixel_depth = 32;
4585 : }
4586 :
4587 : else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
4588 : png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4589 : {
4590 : if (max_pixel_depth <= 32)
4591 : max_pixel_depth = 32;
4592 :
4593 : else
4594 : max_pixel_depth = 64;
4595 : }
4596 : }
4597 : #endif
4598 :
4599 : #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4600 31 : if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
4601 : {
4602 31 : if (
4603 : #ifdef PNG_READ_EXPAND_SUPPORTED
4604 33 : (png_ptr->num_trans != 0 &&
4605 31 : (png_ptr->transformations & PNG_EXPAND) != 0) ||
4606 : #endif
4607 : #ifdef PNG_READ_FILLER_SUPPORTED
4608 : (png_ptr->transformations & (PNG_FILLER)) != 0 ||
4609 : #endif
4610 29 : png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
4611 : {
4612 12 : if (max_pixel_depth <= 16)
4613 4 : max_pixel_depth = 32;
4614 :
4615 : else
4616 2 : max_pixel_depth = 64;
4617 : }
4618 :
4619 : else
4620 : {
4621 25 : if (max_pixel_depth <= 8)
4622 : {
4623 0 : if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4624 0 : max_pixel_depth = 32;
4625 :
4626 : else
4627 0 : max_pixel_depth = 24;
4628 : }
4629 :
4630 25 : else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4631 25 : max_pixel_depth = 64;
4632 :
4633 : else
4634 0 : max_pixel_depth = 48;
4635 : }
4636 : }
4637 : #endif
4638 :
4639 : #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
4640 : defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
4641 : if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
4642 : {
4643 : unsigned int user_pixel_depth = png_ptr->user_transform_depth *
4644 : png_ptr->user_transform_channels;
4645 :
4646 : if (user_pixel_depth > max_pixel_depth)
4647 : max_pixel_depth = user_pixel_depth;
4648 : }
4649 : #endif
4650 :
4651 : /* This value is stored in png_struct and double checked in the row read
4652 : * code.
4653 : */
4654 31 : png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
4655 31 : png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
4656 :
4657 : /* Align the width on the next larger 8 pixels. Mainly used
4658 : * for interlacing
4659 : */
4660 31 : row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
4661 : /* Calculate the maximum bytes needed, adding a byte and a pixel
4662 : * for safety's sake
4663 : */
4664 62 : row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
4665 31 : 1 + ((max_pixel_depth + 7) >> 3U);
4666 :
4667 : #ifdef PNG_MAX_MALLOC_64K
4668 : if (row_bytes > (png_uint_32)65536L)
4669 : png_error(png_ptr, "This image requires a row greater than 64KB");
4670 : #endif
4671 :
4672 31 : if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
4673 : {
4674 31 : png_free(png_ptr, png_ptr->big_row_buf);
4675 31 : png_free(png_ptr, png_ptr->big_prev_row);
4676 :
4677 31 : if (png_ptr->interlaced != 0)
4678 0 : png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
4679 : row_bytes + 48);
4680 :
4681 : else
4682 31 : png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4683 :
4684 31 : png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4685 :
4686 : #ifdef PNG_ALIGNED_MEMORY_SUPPORTED
4687 : /* Use 16-byte aligned memory for row_buf with at least 16 bytes
4688 : * of padding before and after row_buf; treat prev_row similarly.
4689 : * NOTE: the alignment is to the start of the pixels, one beyond the start
4690 : * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
4691 : * was incorrect; the filter byte was aligned, which had the exact
4692 : * opposite effect of that intended.
4693 : */
4694 : {
4695 31 : png_bytep temp = png_ptr->big_row_buf + 32;
4696 31 : int extra = (int)((temp - (png_bytep)0) & 0x0f);
4697 31 : png_ptr->row_buf = temp - extra - 1/*filter byte*/;
4698 :
4699 31 : temp = png_ptr->big_prev_row + 32;
4700 31 : extra = (int)((temp - (png_bytep)0) & 0x0f);
4701 31 : png_ptr->prev_row = temp - extra - 1/*filter byte*/;
4702 : }
4703 :
4704 : #else
4705 : /* Use 31 bytes of padding before and 17 bytes after row_buf. */
4706 : png_ptr->row_buf = png_ptr->big_row_buf + 31;
4707 : png_ptr->prev_row = png_ptr->big_prev_row + 31;
4708 : #endif
4709 31 : png_ptr->old_big_row_buf_size = row_bytes + 48;
4710 : }
4711 :
4712 : #ifdef PNG_MAX_MALLOC_64K
4713 : if (png_ptr->rowbytes > 65535)
4714 : png_error(png_ptr, "This image requires a row greater than 64KB");
4715 :
4716 : #endif
4717 31 : if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
4718 0 : png_error(png_ptr, "Row has too many bytes to allocate in memory");
4719 :
4720 31 : memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4721 :
4722 : png_debug1(3, "width = %u,", png_ptr->width);
4723 : png_debug1(3, "height = %u,", png_ptr->height);
4724 : png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
4725 : png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
4726 : png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
4727 : png_debug1(3, "irowbytes = %lu",
4728 : (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
4729 :
4730 : /* The sequential reader needs a buffer for IDAT, but the progressive reader
4731 : * does not, so free the read buffer now regardless; the sequential reader
4732 : * reallocates it on demand.
4733 : */
4734 31 : if (png_ptr->read_buffer != NULL)
4735 : {
4736 0 : png_bytep buffer = png_ptr->read_buffer;
4737 :
4738 0 : png_ptr->read_buffer_size = 0;
4739 0 : png_ptr->read_buffer = NULL;
4740 0 : png_free(png_ptr, buffer);
4741 : }
4742 :
4743 : /* Finally claim the zstream for the inflate of the IDAT data, use the bits
4744 : * value from the stream (note that this will result in a fatal error if the
4745 : * IDAT stream has a bogus deflate header window_bits value, but this should
4746 : * not be happening any longer!)
4747 : */
4748 31 : if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK)
4749 0 : png_error(png_ptr, png_ptr->zstream.msg);
4750 :
4751 31 : png_ptr->flags |= PNG_FLAG_ROW_INIT;
4752 31 : }
4753 :
4754 : #ifdef PNG_READ_APNG_SUPPORTED
4755 : /* This function is to be called after the main IDAT set has been read and
4756 : * before a new IDAT is read. It resets some parts of png_ptr
4757 : * to make them usable by the read functions again */
4758 : void /* PRIVATE */
4759 34 : png_read_reset(png_structp png_ptr)
4760 : {
4761 34 : png_ptr->mode &= ~PNG_HAVE_IDAT;
4762 34 : png_ptr->mode &= ~PNG_AFTER_IDAT;
4763 34 : png_ptr->row_number = 0;
4764 34 : png_ptr->pass = 0;
4765 34 : }
4766 :
4767 : void /* PRIVATE */
4768 72 : png_read_reinit(png_structp png_ptr, png_infop info_ptr)
4769 : {
4770 72 : png_ptr->width = info_ptr->next_frame_width;
4771 72 : png_ptr->height = info_ptr->next_frame_height;
4772 72 : png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth,png_ptr->width);
4773 72 : png_ptr->info_rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth,
4774 : png_ptr->width);
4775 72 : if (png_ptr->prev_row != NULL)
4776 68 : memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4777 72 : }
4778 :
4779 : #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
4780 : /* same as png_read_reset() but for the progressive reader */
4781 : void /* PRIVATE */
4782 34 : png_progressive_read_reset(png_structp png_ptr)
4783 : {
4784 : #ifdef PNG_READ_INTERLACING_SUPPORTED
4785 : /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4786 :
4787 : /* Start of interlace block */
4788 : static PNG_CONST png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
4789 :
4790 : /* Offset to next interlace block */
4791 : static PNG_CONST png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
4792 :
4793 : /* Start of interlace block in the y direction */
4794 : static PNG_CONST png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
4795 :
4796 : /* Offset to next interlace block in the y direction */
4797 : static PNG_CONST png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
4798 :
4799 34 : if (png_ptr->interlaced != 0)
4800 : {
4801 0 : if ((png_ptr->transformations & PNG_INTERLACE) == 0)
4802 0 : png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
4803 0 : png_pass_ystart[0]) / png_pass_yinc[0];
4804 : else
4805 0 : png_ptr->num_rows = png_ptr->height;
4806 :
4807 0 : png_ptr->iwidth = (png_ptr->width +
4808 0 : png_pass_inc[png_ptr->pass] - 1 -
4809 0 : png_pass_start[png_ptr->pass]) /
4810 0 : png_pass_inc[png_ptr->pass];
4811 : }
4812 : else
4813 : #endif /* READ_INTERLACING */
4814 : {
4815 34 : png_ptr->num_rows = png_ptr->height;
4816 34 : png_ptr->iwidth = png_ptr->width;
4817 : }
4818 34 : png_ptr->flags &= ~PNG_FLAG_ZSTREAM_ENDED;
4819 34 : if (inflateReset(&(png_ptr->zstream)) != Z_OK)
4820 0 : png_error(png_ptr, "inflateReset failed");
4821 34 : png_ptr->zstream.avail_in = 0;
4822 34 : png_ptr->zstream.next_in = 0;
4823 34 : png_ptr->zstream.next_out = png_ptr->row_buf;
4824 102 : png_ptr->zstream.avail_out = (uInt)PNG_ROWBYTES(png_ptr->pixel_depth,
4825 68 : png_ptr->iwidth) + 1;
4826 34 : }
4827 : #endif /* PROGRESSIVE_READ */
4828 : #endif /* READ_APNG */
4829 : #endif /* READ */
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